Wrong Repairs and not correcting the billing

I sent my phone in for repairs by Cell C complaining that the phone does not want to come on. The service department phones me and quotes me R1300.00 for water damage. I dispute this and I mentioned it to the repairs department via email. They sent me pictures to show me the corrosion which apparently is causing the malfunction. I authorize the repairs and the deduction off my account. Did I mention that the phone is still under warranty? The only damage voiding the warranty is water damage - makes you think. ... they repair my phone and send it back .... JUST FOR ME TO FIND THAT THE PHONE DOES NOT COME ON .... I send the phone back, report them on \hello peter"and all of a sudden everybody jump to fix the phone. They even sent me the job card back this time of the repairs done on the phone with a quality check ... REPAIRS DONE WAS CHANGING THE POWER BUTTON ... NOW I AM PAYING FOR THE POWER BUTTON REPAIRS WHICH IS SUPPOSE TO HAVE BEEN DONE IN THE FIRST PLACE FOR FREE COZ OF THE WARRANTY!!!! Just a form of *****ing your money! If Cell C was a doctor and I'm a patient with a headache they will treat me for aids before giving me a headache tablet..."""