Single mother! Needing CSA advice please!!

So here's the thing, back in  January I was becoming homeless with my two children, so I had no choice but to move town (best decision I've ever made for me and my children) anyway their father was super  supportive of my decision (been  separated for 4 years) anyway it's been 7 months now and he's called less than 4 months, I've always been easy on him but he hasnt visited his children and has made a lot of broken promises and sick of chasing after him to get in contact, anyway it was his decision not to see or contact children because he's having another baby with his new girlfriend (he has done this before to another child) so I was wondering can I claim CSA even thought he doesn't want to see or contact his childre? Thanks