Promised $400 mobile promotion denied after I followed Xfinity employee instructions

Promised $400 mobile promotion denied after I followed Xfinity employee instructions
I signed up for Xfinity Mobile, an Apple Watch line, and home internet based in part on a $400 promotional gift card. I returned to an Xfinity store specifically to activate my phone, but an employee told me to activate it at home instead. I followed those instructions. I’ve now been told I’m ineligible for the $400 promotion specifically because I did not activate in store. I’d like this escalated and reviewed by Xfinity Support / Executive Customer Relations.