[Solved] First Post Here - Looking For Any Possible Help

Hello all, I've literally just joined here so please excuse me if anything here is in the wrong place etc, just looking for a bit of a hand like many here I suppose. I'll outline my situation and if anyone does have any helpful comments that would be fantastic, thank you.

Some time back I had a very brief relationship with someone I knew. She was married when I first met her via work, then we met again later. When we met again she told me she was single and we slept together once and she told me she was using the pill, I also used a condom but am concerned she may of sabotaged it somehow, almost immediately after she told me she was actually still living with her husband. I didn't hear from her again until I got a text saying she was pregnant, I rang but she refused to talk with me. Eventually she did, however refused to meet me face to face, said that she was too far gone and was keeping the child. I heard no more until a recorded delivery letter arrived at my flat with a photo of a child. She's written on the back saying she wanted nothing from me, but thought I might like to see my daughter and left only an email address.

I didn't contact her as didn't believe the child was mine, the reasons being;
She was still living with her husband as she told me.
She was in the paper for having a relationship with a murderer who was an inmate at the prison she worked at. She was sentenced for wilfully neglecting to perform duty/misonduct in a public office.

So it was my belief that the child was either her husbands or the inmates and that she had got pregnant to avoid a custodial sentence, which she did avoid. I also believed there was a strong chance she'd been with lots of others to try and escape the prison sentence.

The letter arriving also led to the breakdown of the relationship with my partner at that time.

So I heard nothing more until a Fathers day card arrived with a note saying "Sorry it's late we've been away". Also a letter was sent to my mother at her home address, stating she wanted nothing but wanted to know if my mum would like to be a part of the Childs life.

I'm very concerned how she got my mothers home address as she's not on the open electoral role, is ex directory and none of my friends would know the address, also I'm not on any form of social media. My concern is that she's got someone in the prison/police service to give her the address and also am concerned that she mixes with murderers and what may happen to my family.

Additionally I had identity fraud carried out on myself, someone got a mobile phone contract using my details, but registered from my mothers address. The inmate was sentenced for using a mobile phone in prison and I'm thinking that perhaps she had given my details or used them herself to set up a fake contract and give him the phone to use in prison.

So the other day I receive a letter from the CMS asking for me to pay a large amount of money. The figure they have me earning is £12k higher than what I actually do, I'm really worried as if I do pay what they ask I'll have less that £250 a month to live on after my outgoings as they are currently very high. I've contested that I'm the father with them and am awaiting a DNA test and results.

I've managed to contact her and arrange to speak face to face which is all I've ever tried to do from the initial messages I got from her.

I suppose my main questions are, has anyone else got experience of a situation like this and what did they do?
Has anyone got experience of challenging the CMS's information and adjusting their payments?
I have no issue helping financially if I am in fact the father, but should she not of contacted me first and tried to arrange something before going to the CMS?

Again, I appreciate this is lengthy and has a lot of information, but any pointers would be really well received.

Thank you.