Help needed please ..DLA

Hello I'm really looking for some help and advice ..

We are a family with 2 twin daughters with complex needs who are 6, and a son who is being tested currently for autism who is 10.

My partner and I have recently secured a lives with order for all 3 , on a 50/50 basis. My ex wife and I are separated so share care , I have had contact since the girls we born, but due to My ex wife and I ending our relationship it was been so hard to get consistency, hence the court order I applied for , funded , and secured .

Unfortunately that's where the sharing ends , my ex partner ( we both hold parental responsibility) has and continues to withhold the DlA funding from me , the girls receive the higher rate , carers allowance , care component etc , EACH . Meaning they both qualify for a mobility car ( my ex has 2 , one for her and one for her parents to use ) I've tried the dwp , local authorities, citizens advice but no one can help me secure ONE of the claims for the girls, I'm at a loss as to where to turn , the difference the funds would make are staggering for the lives of my children, even as Simply as being about to go out as a family which we can't at the moment as my small car won't accommodate us all .

Any help or advice on where to trun would be very appreciated.