cancellation issues

I've tried to cancel my service over the phone three times now. Three times I've spoken with a live agent and three times they told me they "completed the cancellation" but I never received an email with confirmation and I keep getting billed for the last two months. 

I've received the same cancellation # twice but still I have an amount due on my account and no email confirmation. I still get emails about the amount due on my bill, however so I know the email is working. 

Details: 
I talked to "Magic" on 23 December who kept trying to sell me on a new package and didn't respect my decision to cancel, so I wasn't surprised when I saw the bill for the full month a few weeks later.

Then, I talked to "Renc" on 9 Jan who said it was never cancelled, but "don't worry, I'll cancel it for you"... Nope, I just got my February bill today (full amount, surprised?).

so I called AGAIN today and talked to "Julie" who said "don't worry, I'll cancel it for you" but still no cancellation email and full amount due on my February bill. 

Xfinity internet equipment has been unplugged since 23 December when I got Metronet installed -- which, I must stay is already way faster, more reliable and better customer service (and cheaper!). 

Someone help me cancel and get my refund for two months of no Xfinity use, please!