Wilshire Consumer Credit - Failure to apply Loan payments to principal of Loan, Charges taxes on Loan Los Angeles California

I reciveved a TitleLoan from this company  24 months ago.  The term of the loan is 44 mos at 340 a month. The principal balance has not move from 5200$ I borrowed at the begining. In fact it has gone up to 5700$, also, I missed one pay 4 days late and the vehicle was repo'd but I reclaim and paid the 1300% and being trying to get the paperwork since for 8 mos. I understand company like this take advantage of people in tuff times but this in not cool...... If I had the money I would sue.  any advice?