So stressed! Arguments with his ex!

I live with my husband, my 13 yr old son and my 2 step children, aged 10 and 8. My step children visit their mum every weekend. My step son, 10, has a very difficult relationship with his mother and because of this has an attachment disorder and has attempted to self harm/threaten suicide at her house twice in the last 4 months.

We have had a great day out with the kids at the cinema today and then dropped them off at their mums at 4pm.

By 4.30 my husband had had a phone call off his son saying that he was angry at his mum as she had been taking his xbox to play on without asking him(doesn't seem like a big deal on its own but this woman has emotionally abused my step son for years and will always take his things without asking, will sell them or give them away to his sister etc anything to wind him up). My husband tried to calm him and told him it didn't matter. My husband then went to work.

At 5.30 I got a phone call off my husband saying could I ring his son. He's really upset but my husband is busy at work. I ring my step son, B, and say what's up? He tells me that his mum took his xbox without asking and that she was then winding him up telling him how she has been playing on it all night long etc. I am very concious that if I don't calm him down he might get a knife to his wrist again so I tell him to take a deep breath and talk to his mum. He refuses and tells me that he wants me to pick him up and bring him home. I explain that I can't (her weekend contact is court ordered and we are currently fighting through court as she wants extra access but doesn't deserve it) and tell him that the best thing would be if he can calm down and talk to her quietly so that he can explain why he is mad rather than scream and cry. I tell him he must go downstairs and speak to him before I will pass a msg to my son to come on the xbox and play with him.

He rings me back 10 mins later saying he has spoke to her calmly but that when he mentioned afterwards that it was my idea she started screaming at him "you act like she's your mum!" I tell him to ignore it and go play in his room.

At 5.45 I get his mum, my husbands ex, on the phone saying will I tell B that he is not allowed to ring me or his dad when he is at hers. I tell her that I've told B he must speak to her when he is mad at her but that I won't stop him from ringing us as I would rather him ring me to say he is upset than harm himself. She tells me that he is now crying cus her ex (B's uncle, yes she slept with her own sisters bloke!!) has rung B and had a go at him. She won't let me speak to him and has turned his mobile off that we bought him.

It all just Pisses me off so much. Tonight is the only night I have without my step kids and I had ordered a Chinese and was watching a film, now I'm stressing over whether my step son is ok or not. We have the final court case coming up next week and I can't wait for it to all be over. Hopefully it will go our way as the social worker who has been involved with her for the last year has also recommended that they stay living with us and only see her at the weekend. She is unable to provide a stable home for them and puts her own needs first. The only reason she wants shared care back is cus she doesn't get any money for them anymore since they moved in with us. I'm just so fed up off the whole thing, I am suffering from severe poor health already and depression and anxiety and i just needed to rant and get all of this out.