OK. We bought 2 Samsung S9 through costco. They gave us a promo sheet. I have attempted to fill out but it would not let me complete it. Called T-Mobile support, told to call Costco, Costco said to fill out on computer not my phone. I can't even pull up T-Mobile.com/Promotions. This is worth $680.
I am getting quite frustrated as I having been screwing around on this for 2 hours. Promotion code is C18SAMB1G1.
try that link
Finally got the job done. Had to use the other cell phone. Could not pull up the correct promotion on computer. Thanks.