How do I get my trade in credit?

That would be great, but I cannot log into my XFinity account to get my account number-I've been getting error messages for 2 days when I try.  All correspondence emails just show the last 4 numbers of my cable account number, and it won't accept my account number for my mobile service-even though it's a mobile issue I am trying to resolve.  The bureaucratic nightmare I am going through is unbelievable.  I have been dealing with this issue since early February.  I have an email from XFinity that my trade in was accepted and I will receive the $750 credit, but it never happened.  I have tried to talk to a real person again using chat and it just goes in circles.  I cannot access my account to get my account number to try and check status, because I had to go paperless to get the best pricing from XFinity.  I am fed up.  Talking to real agents has been a waste of time-I have been told several times that I would receive the credit, but it never happened.  My trade-in is gone, a perfectly fine S 22, and I am now out the $750 trade in value.  I have no way to fix this now.  I'd like to escalate, but have no idea how to do that.  I probably have 20 hours of my time trying to get this resolved, and I never talk to anyone that actually helps.