Refund/Exchange - Consumer Complaint for PEP STORES

I bought a phone for my mother from pep store from the PEP Cell Mitchell's Plain yesterday the 9th of December when I got home my mom had a look at the phone and didn't like it because is not vibrating so I took it back to the PEP CELL store same day yesterday I asked for a refund or to exchange it for another phone from the the store i even told the lady at the counter that even if its means me putting more money to get another phone I will the lady told me that the phone needs to have a technical problem in order for her to send it in for repairs, I am really pissed off because it took the phone in before the 7 days(same day) could be over how can a cellphone store not be able to do returns or exchange on a cellphone