Cancellation being delayed

I requested to cancel my policy by sending an email on the 18-11- 2015 as I was told when I spoke to the call center agent, then after that I never heard from anyone until last week when one of the agents called to tell me I am owing and I need to pay before they cancel my account, understandable but now they tell me I owe them for both november & december, which i don't understand since I sent through my cancellation in november and I thought it went through since no one bothered contacting me, which i thought in december they will debit once then we done, so I sent another request and I was told I will be contacted and 8 days later still nothing and they will pop up saying I owe them for january too yet they the ones who drag their feet. I need my cancellation to be sorted ASAP, I have had it with this organisation.