Sold a faulty phone by MTN

I bought a new phone in August last year on contract. 2 months later the phone started giving me problem and not charging. Would charge sometimes and eventually stopped charging completely. I took it to MTN in Feb and it went for repairs for 2 weeks. I got the phone back on Friday 2 March 2018 . I lost all my data as the phone was cleaned out. Worked for 2 days and now its back to the same issue. Charges sometimes. I am livid as I have only had this phone back for less than 4 days and its back to the issues i had.