TMOBILE Complained to Customer Service about the T Mobile Sparq's disfunctional qualities Fayetteville North Carolina

I tried to file a report with Walmart first about their prepaid phone; the Tmobile Sparq and its many disfunctional qualities after only owning the phone for 30 days. They then turn me around stating that they don't handle problems with the phone and that I should take it to the company itself. 

I then took the phone to a Tmobile store and talked to customer service. I showed them the problems of the phone. They said that because it's a prepaid phone they cannot assist me with the problems.

So who do I go to about wasting my money on phones that a certain company is selling to the public with many disfunctional qualities? I thought it was only my phone but my friends phone is also starting to have the same problems.