Bad customer service

I bought a cellphone on a contract.... 5 months later the phone just went off and didn't want to switch on again.... I took my phone in to cell c and asked them to send it in for repairs. The guy who assisted me told me that it will take up to 12 working days, even on the letter they provided me stating that " Cell c will make reasonable efforts to have the device repaired and available for collection 12 (twelve) business days excluding public holidays" . 13 working days later (not even counting the Saturdays or Sundays- that is business days because they are open on these two days as well) and still no feedback regarding my cellphone. No one can tell me where my phone is. I contacted the branch this morning and the lady who answered the phone did not even try to assist me, she just told me that according to the rules, it can take up to 6 weeks and put the phone down. I phoned back and she dropped the line again, after several times I eventually came through and ask to speak to the store manager. The replay... oooo sorry mam the manager is busy please phone again..... I will never ever make use of cell c again. What a bad experiences and customer service.