When buying a used car is the warranty worth what i thought it was as i thought i would be free of worry for a?

bought the car for �7500 they said i had a full 12 month warrenty at lookers honda now the rear wiper on the bmw has stopped working (motor gone i think) now the company when i called them are saying they have changed owners and i may not now be covered as all the paper work pre january has been shipped their car showroom in nottigham, and for several days iv had no answer any advice please guys