Poor service

I have made contact with these people on several occasions to cancel my contract as soon as the contract term had ended, wich was in February 2015, I was then billed in March again and contacted them again and was promised that it will be sorted out immediately, then I was billed in April again and now it is May and I was billed again for a service that I dont use at all. I am now sick of all these promises and poor service and want a full refund of all the payments taken since my contract expired! The contract was taken out on the 12th February 2013, cell no ***.