Walmart Family Mobile $100 back promotion a lie! Internet

I bought my phone January the 2nd (the Walmart Family Mobile $100 back promotion lasted until January the 6th) and I have also not received any credits on my account. Each month I have called customer service and each month I am told it will be on next bill.

At the time I bought the phone, I couldnt really afford to spend $100 on a phone, but when I saw the $100 back promotion, I figured it was okay to spend the money since I would start getting
it back within the first 45 days of using my phone. 

I am very disappointed in Walmart .  Walmart was always one of the few businesses that I felt could be trusted not to completely rip the customer off, however, they have now shown me they are no different than every other business out there doing whatever it takes to rip off their customers.    I refuse to buy anything else from Walmart