What can / should I do?

I never thought I'd find myself here but here we are, Im looking for some help, advice and support, please.

In October 2023, I left my ex of 11 years.

We had initial discussions and agreements regarding the boys and I stated heavily that I was never leaving my children and didn't want to ever go a day without seeing them but understood what a broken relationship would look like. I was unhappy for 2-3 years as she was very controlling, un loving and cold.

We agreed on a 50:50 with the boys, early on and shared the home between November and February until I moved out to stay with friends around an hour away. I had debt, not in contact with family so leaving was hard and my children were what kept me there for so long (ages 7 & 4)

I understand that I had a lot of stress with family, and trauma from them built up over the years and went through a very difficult spell at work during our final time in the relationship. No doubt this took its toll on things but it didn't change how I was made to feel by her.

We initially shared the home until I moved out, before leaving I asked about relationship counselling, she refused. I tried to suggest date ideas, wasn't interested, after leaving I asked about setting an arrangement for me having the boys, she refused, I suggested mediation, she refused. we finally got somewhere when I suggested we sat down with a freind a piece to try come to decisions. We had two separate meetings and she did everything she could to get her own way and not allow me to have my boys, she said I wasnt trusted with them, she said I wasnt capable of having them, my freinds home wasnt safe etc etc, all items were untrue. My friend works in the NHS in family support and mental health and was brilliant, she highlighted my ex’s inaccuracies, such as, if I wasn't trusted then why leave me with the boys to get a hair cut, why let me look after them single handedly for days during the time we shared the home post separation.  Shes since accused me of DV which I was horrified by and I believe used this as a tactic to avoid mediation, I looked into this and can happily take blame for causing arguments and blaming her for what I felt were her shortfalls in the relationship. This was maybe 3-4 times over a 2-3 year period. I was so frustrated and pointed out to her what was at stake and she did nothing to help the situation other than her standard of ignore and bury her head in the sand.

To be truthful there was one occasion which I'm ashamed of where we were having an argument, I hit a door in pure frustration, she called the police and took the children away. There were no charges, arrests or statements made yet she's dangled this over me ever since.

We finally got to an agreement for the short term which was for me to have the boys every other weekend and the ability to pick them up mid week and go for dinner etc when I could.

The long term was based on when I moved back into the area and we would transition to a 50:50, she wrote the agreement and emailed it to me. Since then she has broken nearly every part of it, it included items such as my possessions being able to stay in the home until I was settled and on my feet - she broke this and told me with 30 minutes notice one day to collect all my belongings.  the sharing of our family dog, she wont let me see her.

Shes been impossible to communicate with, ignored me, not replied to messages, has realised that with AppClose (suggested by my solicitor) that if she just ignores notifications then she can pretend she hasn’t seen messages yet she is glued to her phone.

Around June time, things were even worse, she found out that I was seeing someone and just went into a whole new level of spite towards me. When finding this out, this was when she told me to collect my belongings with no notice. I took what I could and left. After this, she started black mailing me for money

Moving on, I have now moved 3.5 miles away from our children, I have bought a lovely home for us and based my finances on being in a 50:50 situation. my ex has pulled this away from me and is now open to mediation which leaves me baffled as I always believed she fabricated DV as a reason to not do it. this begs the question, has she been told that there was never any DV?! 

I'm getting crumbs of time with my boys. She's relying on grandparents to have them two nights a week after school. She will only let me have them on a Monday evening because it's convenient for her, but I'm not allowed to have them overnight. 

At present, im having my boys from school on a Friday every two weeks until around 4:30-5 pm on Sunday. On a Monday, I collect them from school at 3:15 and get a couple of hours with them before needing to take my eldest to Beavers at 6 pm and drop them both back to hers by around 7:15

I did my first mediation session today, which she doesn't know about. I asked her to call me this evening whilst face timing the boys which she agreed to. an hour later, I got a message saying she wouldn't be calling. She's been horrendous with communicating with me and is causing a lot of anxiety, and depression and leaving me wandering around my home alone, feeling fed up and considering what the point of being here is... I've had some very dark days whilst all the time, I'm feeling like I'm being punished. any time I try to talk to her, she just walks off, anytime we are on the phone, she hangs up. Im going out of my mind as I'm in a financial mess as all my outgoings for buying my home were based on a 50:50 arranagement, Im without my children and I have no money to seek legal advice. 

I purely wanted to speak with her this evening to hold out an olive branch, ask her to reset, and focus on co-parenting with me rather than against me (which is something I've lost count of asking) I made a mistake this evening and went around as she wouldn't reply/respond. We are using App Close, and she's learnt that if she ignores messages, it won't show she's been online, and she can just say she's not seen them - creating more of an issue... I arrived and lightly tapped on the window, I just wanted to talk and try to let her see I'm not a bad person, I'm just desperate to have my children. within a minute, I received a message saying to leave, so I did... 

Im now starting to feel like she will paint a picture of us being unable to communicate so that she can refuse / manipulate the mediation into not having to talk things through with me... I get the feeling that all along, all she wants to do is go to court. This has been confirmed by what have felt like threats from her saying ''if we cannot agree then someone else will'' what she means is that if she doesn't get her way, she will take me to court... 

What can I do?! Her behaviour is atrocious and I never ever thought this of her?

My payments to her are privately arranged, can I stop paying to fund a solicitor? When I have my children, can I just say no to them going back?