Billed for cancelled mtn contract

I was misled by a representative from Mondo MTN namrd Chris at Rewards Co who sold me a contract under false pretences on September 11. I then called on Sept 12 to cancel and find out today, Sept 19 thay my request was canceled and my contract is still active. I have reached out multiple times via email and over the phone with no help at all. I now have to pay a cancellation fee whereas I canceled this within the cooling off period and am being billed for this contract which I have not even used at all. MTN is the worst.