FAULTY PHONES, POOR REPAIRS

I got a Nokia Lumia from Cell C mid Feb 2015. The phone stopped charging 30 days later and I had to take it in for repairs in April. I got the phone back on the 30th of April only to find that it has the same malfunction. How was the device sent back to me in the first place?! I understand that this has to be repaired by the manufacturer but why wasn't the device checked before I collected it from repairs the first time! You are the service provider at the end of the day and still making money from my monthly installments!! <br> I'm now paying for a phone that is always at repairs and at an inconvenience! Do your cheap call rates also imply that you provide such poor service?!!