Trade-in amount

Initially I was excited to switch to T-mobile. The sales reps in the store were very helpful at explaining the promotions we could take advantage of as new T-mobile customers and we were confident we understood what our bill would be every month. We were able to buy 2 Samsung S22s for the price of 1 phone and trade our old phones in for $400 credit….or so we thought. Two different in store sales representatives looked at our old phones and told us that we should receive the $400 credit for each device. At no point did the representatives warn us that we might not receive the $400 credit and they asked what model of phone we had to insure we would receive this trade in value. They even told us that initially the phone's trade in credit would say $30 but once the phones were received that it would be changed to $400 and we would see this trade in credit on our bill spread out over 24 months. It has been ~4 months and we have only received $30 credit for each phone. When I contacted T-mobile to double check why I saw $30 on one month, the rep assured me that I would see ongoing $30 for each phone for each month. Well, this still hasn't occurred. Now dealing with a different online rep, they are telling me that I only have the buy 2 for 1 phone promotion. So it feels very misleading that what the in store sales reps are telling us does not match what the online reps are saying. The online reps are making it sound like this trade in offer does not exist and are telling me that the fair market value of the phone would be applied of $30. I'm just disappointed and I was expecting what the sales reps at the store had explained and that was my expectation, I wouldn't have traded in my old phone for $30. Or at the very least if the store reps had told me that the trade in value could vary I would have understood. Now the online reps are telling me that expectation was wrong and that the promotion didn't exist and they just keep reminding me that I have the promotion of buying 2 phones for 1.