Replacement iphone won't activate

I purchased an iPhone 12 Pro Max from Xfinity to replace my old iPhone XS (also purchased from Xfinity). The new phone says it's still not activated after two days. I talked to Xfinity Mobile twice yesterday and they told me to keep waiting. Today, the Xfinity Mobile web site shows it's activated but the phone says it's not and it won't work.

I've tried using the old SIM card in the new phone and it works, but I'm worried that doing this will confuse my account.

I tried calling Xfinity again today (Sunday 11/15) but the recording says the office is closed. 

Any suggestions would be appreciated.

Thanks