Forged signature on Hp agreement

[Guest]

Hi. I purchased a used car from a dealer on Hp. I applied for finance over 4 years. Unfortunately the dealer ot finance from their company over 5 years at a much higher interest rate, rather than telling me, the sales rep tried to copy my signature from my driving licence ( a very bad attempt) it has taken me 2 months to get a copy of the agreement from the dealership. On receiving the documents I contacted the finance company to advise them the signatures on the credit agreement and direct debit mandate was not mine. They told me they will look in to it. Unfortunately this was a month ago and I am still no further forward. What should I do next. The direct debit has been cancelled and I am still making the monthly payment via bacs