Not returning calls and not responding to email

I cancelled my car insurance contract with them in 2013 and they continue deducting premiums from my bank account even after I asked them to stop that on the 9th of February 2015. They asked for my bank details and promised me a refund as soon as they get the statement from me, but to date nobody has come back to me. I have sent them at least emails [Email Removed] and have called them at least 6 times and still no response, instead on each occasion I am told my consultant is busy on the phone. .