Complaint Review: Costco and T-Mobile

I bought 2 T-Mobile iphones from Costco back in early May 2015 and was promised two $25 Costco Cash Cards.  It is now November 17, 2015 and I still have not received my cash cards.  I have called Costco - been transferred here there and everywhere.  No-one wants to know.  T-Mobile don't want to know, so where do we go from here?  Is this false advertising and who is responsible.  I'm pleased that other people have been able to get their cash card rebates, but as I wrote, NO-ONE  In all fairness, however, Steve has been very helpful and has been trying to get my rebate for me. He has forwarded all of my information countless times to managers, district managers, etc., with no results whatsoever. The reason I mentioned his name is because he is the manager of the kiosk and should have a lot more authority than he does. A rebuttal stated not to blame the carrier. Then who's fault is it exactly?