Xfinity has wrongfully sent me to collections and will not confirm in writing that my service has been canceled

I have talked to multiple people and departments and each time it is a different story.

"Your service has been canceled."
"Your service actually wasn't canceled before but it has been canceled now and you won't get billed anymore"
"Your service has absolutely been canceled and you will get a refund but not until the next billing cycle and we can't send you any verification of that" 
"Your service never got canceled and you have to return your equipment"
"Your service never got canceled and you have been sent to collections"

"Your service did get canceled two months ago and you've never had any comcast-owned equipment but you got sent to collections anyway"

This should be illegal.