Discovery Insure Pathetic Customer Service

I received a my annual premium increase letter from Discovery Insure and queried how they could justify a 13% increase considering I had no claims history I was transferred to the retentions department and after some back and forth we settled on amount and they sent me the revised policy with the new amount. Fast forward to June they debit my account with the amount with the 13% increase I queried initially , I called them to query this only to be given a further run around and kept on hold for ages.