Refusal to pay full refund for cancelled insurance

I am not happy with the way I have been treated by the 1st for Women insurance. In 2012, I made a call to have my insurance for Opel Corsa 1.4 cancelled and in place of the Opel corsa I put in Nissan Micra which I also shortly cancelled.Fast-forward May 2015, I realise I'm still being debited a monthly fee for a touch-up cover for the Opel Corsa after having cancelled the insurance. Upon realising, I cancelled the insurance and asked for a refund. I was told that the cancellation department will contact me with the details of the refund. Eventually, i got contacted by Nadine, who told me my matter is under investigation and I should provide the insurance with the proof of sale/change of Ownership for the Opel Corsa in order to be refunded as she is also still busy trying to locate the recording.I then provided Nadine with a settlement letter and a copy of the settlement cheque that the dealership provided to me as they could not locate the proof of sale since the sale happened back in 2012.Today, Nadine told me they will refund the premiums paid over a period of 1 year. I paid premiums for almost three years for the \cancelled"insurance and a car that i do not own. This is unfair."""