Faulty cellphone

In May last year, I bought a Stylo cellphone from Pep Clearwater Mall. Around September the phone couldn't charge and I took it back for repairs. When taking it back they took the original slip and never gave me a copy. I then received a replacement phone as the initial one was irreparable. A month later (November), the second phone also had the same issue, I took it back and it was replaced. When I took it back I indicated that there is something wrong with either the brand as I keep getting the same problem . I was given a replacement phone in January and the phone has started again with the charging issue. I currently do not have any paper work for the phone as the last time I returned the phone they told me they will call me to come collect paper work but never did. It is evident that the Stylo phone is the problem and I do not know if they will take the phone as i do not have any documents with me and secondly we are nearly the warranty end date. Can PEP either reimburse or replace the current phone with a different brand as clearly i cant use the phone form more than two months without having same issues and i bought the phone to use for business but i cant rely on it as it keeps dying.