Ex isn't supporting financially

Hi all,

My first post on here, so hi everyone.

My question may seem like a strange one to a lot of people, as I am aware, I am in a privileged position when it comes to access/relationship with my son. But I was hoping that someone could point me in the right direction or bring closure to a constant issue between my ex and me when it comes to our son.

10 years ago, my son's mother and I broke up, since we broke up he has spent virtually every weekend, from Friday to Monday morning with me up until May 2022. In May 2022, my son came to live with me as she had another child, he is now 13 and things changed too much for him. My son and his mum doesn't have the best relationship and our parenting styles are very different which is why I think they clash a lot as most of his time away from school has been with me. Sometimes she can be a great mum, other times, not so much. I have tried to encourage both to maintain a relationship, but my ex makes that fairly difficult, I can count on 2 hands the amount of nights he has stayed with her since May 2022 and she doesn't try too hard to spend time with him. He goes to hers for maybe 2 hours after school during the week and that is it, we live close by so it is easy for him to do that.

I am a single dad and I do earn enough to support both me and my son, so money isn't an issue on my side, however, my ex barely supports or offers anything financially, she still claims child benefit for my son and I would imagine still gets tax credits as I can't imagine she would tell benefits if there was a change in circumstances, but she doesn't spend much on my son. She works part time and her partner works full time, but they are on low enough income to claim. I believe she should be contributing to his keep and actually if she were to support financially, I would just put the money in a savings account for him, so he can use it for when he is 18+. I have constantly asked for her to split costs for like school uniforms and to even give the child benefit she is claiming to our son, but it is a struggle to get anything. I didn't want it to get to the point of having to go to CMS etc, but out of principle, I feel I should. I can't claim child benefit as I am over the earnings threshold to claim even though it is just my income (broken system in my opinion). Again, the child benefit would just go to savings.

Regarding CMS, she tried that on me a while ago even though I had him almost 50/50 responsibility as they only count nights and still gave her money every month, she wanted more, so they do have a case open still and they won't cancel it because my ex won't tell them that my son lives with me and they will only close it if she does (looked online for this info).

I now feel like I need to go through official channels so that she starts paying what she should pay. I am sure if this was the other way around she would be doing everything she could to get every penny out of me. I believe the system is set up to favour mothers no matter the circumstances, so I guess my question is, what do you all suggest I do? What channels can I go through to start getting her to contribute financially? Where do I start?

Any help would be really appreciated and happy to elaborate on anything I have said, as constructing stories isn't my strongest skill.

Thanks everyone

Mike