Promo Help/Questions

Hello! Just recently switched my wife's number to T-Mobile (port-in from AT&T); the rep at Costco told us that even if she got a deal with a new phone, she could still get the $400 promo in Costco Shop Cards. She even confirmed with him that she would rather use the BYOD rebate and then come back for a new phone after receiving the $400 in rebate cards, and he assured us that no, we will still get the $400. ***We DID NOT switch to Experience Beyond, I am currently on Go5GPlus Military and added her to that.*** My wife's dad goes in the next day, talks to a different rep, and he tells her dad that the lines getting promotional phones/new devices are NOT eligible for the $400 in shop cards... who is being misinformed... me, or my father-in-law? If we are still going to get the $400, my next question is: do we need to put in a rebate code online within 30 days, or is it automatic? I don't want to get screwed by not putting that in within 30 days.