Gift Card Issues

I signed up for Comcast Business services in late November. I have spoken to multiple reps that have assured me the $400 gift card associated with the package I signed up for is going to process as it was noted on the account. Time has come and gone with no gift card. I have been given the run around for multiple hours at a time on multiples occassions to only be told nothing more than I originally came in knowing. I have been given two case #s and still, nothing. Why is this such an issue? Why does Comcast guarantee these things then can't follow through? It's as if they want to play the waiting game and see who gives first. I will not give. I want the gift card that was promised to me. I assume this is an issue not only with business accounts? My brother is having the same issue on his personal account and is ready to pull the plug after signing up just two months ago. It's absolutely ridiculous.