ex wife tears our Kids British citizenship registration form

Hello guys
We were applying for UK citizenship for our kids who were all born here and over 10 years old (never left the UK)

I currently have an FLR FP outside the rules pending and my ex wife knows this. We had discussed registering our kids (who live with her) but repeatedly, she has refused to participate with me

Today, She came out of the blues with forms, and asked me to sign some home office forms and refused to tell me anything more and kept yelling if I refused, she would take the kids away

To stop our kids crying, I finally agreed, but after contact (with my kids) was over, I would sit down to read and discuss it over with her, so that we jointly do so

She vehemently refused and tried to take our kids away, who started crying, when she realized she was unable to, she demanded I sign or she leaves and warned our crying kids, shouting your dad wants to destroy your future

Eventually i brought out my phone, recorded our kids and then went over to her and signed them, telling her, if she tried to do anything behind my back I would take her to court based on the video recordings, after contact was over, she torn the forms infront of our kids and walked away and said she will not sign anything else or discuss any future of our kids with me

I had taken her to court a few years back and have a contact order in place, which she has refused to extend beyond 2 hours supervised contact twice a month and she always comes late

Kindly advise

I dont know if this calls for the family court or what ? after all its our kids future

many thanks
Zibi