Please help, Uploading evidence

I have a hearing coming up to dispute that he took the money ftom U.C when daughter was first born? Not me and we didn’t need it. When we split around this time last year U.C says I gotta pay it back as was joint claim n I should have known about existing debts? I didn’t. I can prove I didn’t receive money I can prove I applied for sure start grant I can prove I went thru my last job to try get maternity leave/alliwance with them but couldn’t n had to claim DWp instead - y would I need universal credit too? Should I upload his abusive conversations to prove his abuse too,