Xfinity Mobile Care added without my knowledge

I purchased a new Samsung A35 on Aug. 15th from an Xfinity store.   Two weeks later I received an "insurance policy" in the mail explaining how Mobile Care works and what it covers.   I knew nothing about this policy; was never informed of it at the store.   It seems the customer representative in the store added it to my account without my knowledge.   It costs $15 a month.   This is something I never would have purchased.   Luckily I read all the paperwork I received in the mail and found the number to call and cancel before I was billed.   Is this how Xfinity conducts business?   I find this to be extremely deceptive.  I also never received a receipt or any proof of purchase for my phone.   The rep in the store said it would come to me electronically.   So far I've received nothing.   This is unacceptable business practice.