When I was living in Australia I was in a relationship with a man. My daughter was planned with my ex-partner. He met someone else while I was pregnant and we broke up. He had moved to China a couple of months before I gave birth.Before I was pregnant we had just built a house and moved in together but my name was not on any of the deeds. We were together about a year but only lived in the new house for about 6 weeks as it was being built most of the time we were together.When our daughter was born he paid CSA for about 12 months but he applied for a change of circumstances several times to avoid paying, including stating he was on a nil income when earning AUD$180,000pa.He even applied for a paternity test and refused to pay CSA. I guessed that it was because he was going to leave the country again and I agreed to it right away but he took months to go for his test; not going to the court ordered appointments that he has requested.With all the previous attempts to not pay and due to the wording in the letters from his lawyer; never saying that he thought iI had cheated, but rather he'd not seen a birth certificate, it was clear that this was all so I couldn't file a departure prevention order stopping him leaving the country with a CSA debt.Sure enough, he had moved to Bulgaria by the time we had to go to court for the results proving he was the father.CSA had accrued in this time and he agreed to pay it if I agreed to sign something at the lawyers saying I would not go after his house or estate. He earns AUD$180,000 pa and the house is worth AUD£700,000.I went to his lawyers to sign it with the reassurance that he would pay AUD$9000pa (£4750).When our daughter was 3 years old, and he had never shown any interest in seeing her even once, I moved back to the UK to be with my family. Our daughter is registered disabled and I need support from my family.He is married now and they had a child 2 years ago so my CSA went down. I have had my CSA amount changed so much in the last 9 years, which keeps going down, and currently at AUD$134 (£70) a month. What can I do?I have no idea where he lives now. He has changed his name to his wife's name on Facebook and while it says that he is in Perth, I have no idea if that is the case.