new upgrade already 2nd hand and not repaired

I recently upgraded barely had the phone 2months and it started making a white screen shortly after that my speaker went I took the phone in early Dec 2015 it went in for repairs I got a message on the 12th Jan to come and collect my phone only to find nothing was been done on it. it was sent back the same day now I have to wait another 4-6weeks for not my fault but for theirs and I'm a working woman and they cant even borrow me a R99 phone which is the worst part...if not that our accounts is always a stuff up...this is not our first time having an issue with Cell C and now my brand new phone is already in for repairs this is truly unacceptable.. Now I have to pay my full installments for a 2nd hand upgrade that may lead to more problems in the future due to the fact that its already going for repairs for the 2nd time im truly dissapointed in this service and the phone i got all my contracts is nearly finish i will close all of them i refuse to deal with this type of service and quality