5K bill in international charges

I went to Mexico in August to bury my grandmother. We recieved a notification action to accept global pass upon entry in  Mexico which we accepted.  Now we have a 5k charge for being there for about 10 days.  Coming back k from that expense and having to call xfinity 3 times to be told by staff I was in an outdated plan, and that this should not be charged and they would change and remove the fees, to today speaking to someone else after no response to my request to adjust the bill since I do not understand why it’s been so high. I have called xfinity in the past to notify my parents were traveling and was told by xfinity staff no need to call anymore and now my plan is outdated and Mexico is no longer part of global pass? Why then send a message to accept it? It’s ridiculous  that I have to pay such a high amount without any discussion and I need to do a payment plan? Why when I don’t trust you as my service provider anymore! I am so upset that I have to possibly dispute this  and pay such a high price e when it was not well communicated or my plan all of a sudden no longer had Mexico as part of their plan.  Please help resolve this issue