Unhappy Mobicel berry purchase

I bought a Mobicel berry at Pep stores Grassy Park The phone is very slow the touchscreen struggle to open the keyboard to type internet very slow. I tried to return it to the store for an upgrade and the customer service was very bad. They wont allow to change but say they rather send it back for service. The phone is not damaged its less than a week old but not happy with the way it functions Still no help from Pep stores