MTN THE ZONE ROSEBANK

I took a contract with mtn the Zone rosebank on Aug the 15th used the phone till end of Sept the phone when blank remember there have a warranty so took the phone back they took it for a month while of Oct I didn't have a phone came back 1st week November it worked for 7 days did the same thing again so told them I don't want it anymore I want a nee phone said to they will speak to work haiwei to give a phone and see what they can give me since they debited for 3 month and I don't even use the phone to my surprise now they telling me they can't give me a phone there nothing they can do they giving me the same phone that they took for repairs and did the same thing guys I work hard for this month but they just making me a fool they told me hawei will decide if they give me a phone not and I don't have a contract with them I don't understand why I should deal with the supplier cause I app**** for new phone their perthetic service mxolisi