Faulty device after 7 days of receive

I took out a contract(Sony M4 Aqua) and with Telkom on 24/06/2015 Sony M4 Aqua and the phone was delivered after 5 days.<br> Within the very same week, the phone stopped working properly. I sent the phone back to Menlyn store. The phone was booked in for Repairs, it took closed to 3 weeks for the phone to be back from repairs, it was sent back. The phone worked only for 4 days, and then it stopped working properly. My concern is I pay for the phone every month, and its not working properly and I can't afford to send it back again for it to be fixed as I use my own money to send it. There is no Telkom branch in my town.