T Mobile ripped me off with Thanks giving samsung S7 trade it offer.

- Member Since: Jun 23, 2017
I have been a loyal customer of T mobile since last 12 years and never had such a bad experience like this before. Last year during the Thanks giving weedend Tmobile had Samsung S6 trade in offer with samsung S7, where in you can trade in a paid off Samsung S6 with the Samsung S7 , so I have paid all the balance due on Samsung S6 and traded it with S7 , after doing that customer rep told that they will send us the return shipping label for Samsumg S6 with the new samsung S7 phone and I was also asked to pay the monthly installments for samsung S7 until they receive the samsung s6 back (which they said will refund me once they receive the S6 phone back).
After I shipped the Samsung S6, I have called them multiple times ( December, January, February, March, April) and everytime time the representative told me that I will get the refund in a month and sometime the representative even told a week but didnt receive it till now. Later when I called them this month( june) after 2 escallation i heard a total different story which no previous representatives told us, that is the plan I was in was not applicable for the thanksgiving deal which no other rep's that I have talked to mentioned it till now.
I have questioned them below and they have no answers except " We are Sorry its not your fault but we cant do any thing"
1) If My plan was not applicable why did you let me trade in and why did the rep didnt tell me that?
2) Why did you send me the shipping label for returning the paid off Samsung S6 phone?
3) Why did the previous reps didn't mention this until today?
4) How can I get the Samsung S6 back if my plan is not applicable for that deal? for this they have bluntly said we cant return it.
I am feeling help less now they are not returning my paid samsung S6 phone and forcing me to upgrade my plan to avail this offer, which will cost me 90$ more than what i pay now. Can someone please guide me how i can get this problem addressed.