Debit Order

I had insured my mini cooper with A Forbes, on the 28th of Feb 2015, i traded in that car for a mercedez GLA, 200, i took insurance with A Forbes again, at the dealership i was told i need not worry about cancelling the insurance for mini because they will recognise that i took another one for a new car and automatically cancel it, now on the 28th of Feb, a debit order went off for the insurance for the Mini, on the 19th of March i was trying to get a quote for a package that include household goods and out of interest i asked if the insurance for mini has been cancelled to my surprise it wasnt and thats when i asked for it to be cancelled because thats wrong. Now, i realised only when insurance debited twice for the new car on the 1st April that the debit order for Feb for mini shouldnt have gone out. i paid for the car i no longer have? Unless i am misssing something here, i need someone to contact me and resolve this because the lady that assisted me on Friday was clueless she said my acc wasnt debited on Feb and i know for sure and have record it was debited.