Handing me over for an account I do not have!

I had signed up with MWEB to host a website for my business. After I had signed up I noticed that their layouts were exactly the same as the provider I was using so within 2 days I cancelled. MWEB acknowledged my cancellation and said it would take 30 days to take effect (this was in August). They then debited my account for more than DOUBLE the agreed amount after the cancellation and now I am constantly being harassed to pay my account and that they have handed me over. I have tried contacting them and I have sent countless emails and no response. I was warned by MANY people not to go through MWEB but I ignored that advice and now I regret it!