wont cancel policy since July 2015

They are still debiting my account each month after they refused to take a verbal cancellation they said I should write a letter with my signature and I did so but still they deduct money from my account.I have stopped the debit order then they just deduct from another account.I want my money back from July 2015.I cancelled this policy as for months I didn't receive any information from them so they deliver no serviced.If this goes any further I will take them to court.