I can’t buy my council house because I pay for ex’s mortgage

After 17yrs of paying the c.s.a for my 2 children, & my ex-wife contacting the c.s.a every year for them to ask for an update on my finances..(this is taking the biscuit). My youngest daughter is 18 yrs old now & my ex contacts the c.s.a 9 months before my daughter becomes 19yrs old to try & get more from me before it stops.

I payed arrears for 16 yrs & yet when I explained that when my youngest became 16yrs old my ex never recieved carers allowance.. so I should get that all back.. their answer was no..

She has a mortgage, a new car, full-time employment.. I cant even buy my council house because I’m paying for her mortgage. It’s my wife of 12 yrs together I feel sorry for…she has been by my side for 12 yrs while this has went on.