Help! Received $1500 bill

I received a $1,500 bill from Xfinity Mobile for roaming, and I’m shocked. My husband and I cannot afford such a large bill.
When we signed up, we were told about Unlimited Canada & Mexico, and we agreed because we travel between the U.S. and Canada. I also tried several times to add Unlimited Canada coverage to my account. I was finally able to activate it, but my bill is still increasing with additional charges.
Can someone please help review my account and explain what happened? Has anyone had success getting unexpected roaming charges reduced or credited?

Please help me review this situation. I do not have this amount of money and I will not be able to pay a $1,500 bill. I would really appreciate any help, adjustment, or solution from the Xfinity team.