The worst Pep store ever Jabulani Mall Next to MTN

I purchased a Mobic cell phone from Pep store Jabulani Next to MTN store in the mall, i am having endless issues with the device and when I want to return this phone due to its technical issues I am told this cannot happen. I am not satisfised as the phone is still in the box and was set up in store , i want this resolved now and i am not even sure who to speak to to get this sorted out