Problem cancelling insurance on a paid up product

Hi there<br> <br> I have phoned round about the 28th of April to cancel the extended insurance on my fully paid Samsung Aircon (which I did not approved in the first instance), I was assured by your customer service desk that it was cancelled and I will not be billed for it again.<br> <br> The reason why I phoned and not mailed you is because i have a lot of unanswered mails and wanted to make sure that you receive the message.<br> <br> Today I received a letter from your office stating that I am in arrears with the insurance amount! When I phoned to find out why the insurance was not cancelled as promised I was told that your office never received my phone call and that it can only be done via written instructions.<br> <br> Please sort this out.