Fed up with this ****py phone!!!

I took out a S5 on December 20th, as my upgrade was due. I literally had the phone for two whole weeks before the issues started arising. I then had to take it to the samsung store in the Waterfront to get the software repaired only to have the 'same' issue weeks later. I then brought the phone to cell c store where I purchased it, only for it to get sent to JHB for repairs again. So I received my phone today(14/02/2015) after the couple of weeks of waiting Already, for it to give me the exact same problem the exact same night, Now I am furious because I am paying for a Contract that is costly yet the quality of this phone is continuously giving me Problems!!!! I've had to jump between numbers and run back and forth for this phone!!! I am really angry and frustrated with the quality of cell-c services and the cell c product itself! I Need this matter to be sorted out as a matter of Urgency!!!!