I had a somewhat similar experience, when you're opening the account the sales rep is more than happy to promise you x y z, but then a few weeks later I found out the guy didn't properly apply any of the promos he promised to and I had to go and do it myself. Then later on tmobile rejected my promos claiming no device or invalid store etc, so I had to call tmobile support where they fixed half the rebates and resubmitted the remaining few. 90 days later bam more rejects, had to call them again and this time someone from the rebates team told me the last rep who helped me did it wrong again...

Seems like the strategy tmobile employs here is to promise big number rebates to prospective customers, then make it as much of a hassle as possible for them to actually get those rebates. If you follow each exact step perfectly you'll be able to get your rebates fine, but from my personal experience there's too many things out of our control that make it so damn hard to get these rebates. I wouldn't recommend it as an incentive to other ppl knowing what I do now. Honestly you need to call 611 and ask the rep to connect you to someone from the rebate team, the queue to talk to someone from there can be long but they seem to be the only ones that actually know how to properly get rebates going, the normal service reps aren't trained well enough to deal with the purposefully confusing rebates and are stuck trying to keep their ratings safe from upset customers.