Is there anyone based in the United States with actual authority that can help?

At this point, I'm SUPER frustrated with the level of customer service provided by Xfinity.  We had out home internet with them two years ago, and got fed up with Customer service back then and got lured back by a mobile trade-in of $600 for our iPhone 12 Pro phones and decided it couldn't be that bad...

Executive Summary:  We joined Xfinity from Verizon on 1/2/25.  The salesperson at the store accidentally entered one (1) incorrect IEMI number for my .  The last digit was entered as a 1 instead of a 2; the correct IMEI line ended in a 2 and the second IMEI line ended in 1, so it was an honest mistake that I understand.  I didn't notice this, nor think I needed to check it, sent stuff off and Assurant denied my particular phone; my wife's was okaay and has been getting the monthly trade-in credits.  For something so simple as a mistake made by an Xfinity representative, the overseas customer service has been pretty ineffective.  I'm a person of principles expecting when a promise is made that it be carried through.  In this case, the promise was a trade-in credit for the phone.  I sent the phone in to Xfinity in good faith that they would make the credit; however, because of their mistake, they haven't made attempt to correct the issue causing it to not be accepted and make their mistake my problem.  I've spent no less than 12 hours dealing with various customer service representatives to no avail.  I'm seeking help from someone more sympathetic to their mistake and make things right.  When an employee or representative of your company makes a mistake you figure out how to honor the deal - especially in this case.

There have been numerous ECMs created, and the overlap of a few have possibly caused issues.  As of last night, there is a new ECM created that I'm 1% hopeful will result in anything positive.  My faith is pretty much gone with Xfinity at this point.  Someone at Xfinity (in the US) please help.