15% Premium increase without notification nor does anybody return my calls to cancel policy ?

<p> I have had motor insurance with Miway for over the past year . When I approached them for quotes , their service was incredible and they promised the world of happy motor insurance cover. This year , upon the anniversary date of my policy I decided to call and in ask for my policy to be reviewed only to be told that my premiums are going to increase by a staggering 15% which in turn results to almost 50% of my car installment. No notifications were sent to me regarding the increase , which means I was in for a huge suprise when my next debit order was to be processed. Never the less , upon stressing my concerns with a senior consultant, I was told he will call me back with various options, to date and nothing has been done ...I received an email to state my policy has been updated but I didnt authorise any changes ? I've had enough of this and decided to eventually cancel my policy as they are certinaly not willing to do things 'my' way. I have been arguing this fact for a long time now and every time I get prompted a senior consultant will contact me to cancell but its been a week and I have not had any response to cancel ? My debit order is due tomorrow ! What does a guy have to do cancel his policy ? </p>