Paternity tests and the CSA

I have been in dispute with the CSA now for 3 years over the paternity of a child they state is mine, at first they claim to have not received my letter of dispute.

Then they sent the form for me to ask for a paternity test to a random address….now after what has probably been over 100 calls to them they state the only way to get a test is to take them to court, which i think is a good idea except for the fact that i’m one of those lucky few who earns to much to get legal aid and not enough to afford a solictor, now i’m fairly sure its possible to do it on my own as the C.A.B. is a bit vague on the situation. does anyone have any advice that could help me like which forms to apply for and such alike.

I’m even trying to prove that i wasn’t present in the same county when the child was registered…

any advice would be greatly received…..