I retuned my equipment at Xfinity local retail store, but they couldn't print out a receipt for me

I canceled Xfinity internet service and it has not been easy. However, what comes next is even more ridiculous. I returned the equipment (gateway/router) to a reail store at Clear Lake Houston, Texas  they were not able to print a receipt for me (never heard of).  They did suggest me to take a picture of the equipment, and I did, but don't know how useful it would be when dealing with Xfinity.   I was also told that I would receive an email about the return of the equipment.   I have not receved any email.    I tried to use live chat to check if my equipment has been marked as "return",   But was denied to chat and was asked me to call a 800 number. I called and after struggling with (intentionally) poor design virtual agent, and finally was told the waiting time is 45 min. They also offer an option sending me to live chat, and I was denied to use live chat again as I cancelled the service.   I would appreciate any suggestion regarding how to deal with Xfinity.