Refusing to provide a loan phone after phone got booked in for technical issues!!!

I am beyond furious!!!I took a phone in August through a contract.The first installment was taken in September via prorata.Its only been 2 months since I took the phone but I am experiencing technical issues already!The sim card doesn't want to read because it put itself on flight mode and doesn't wanna switch off flight mode even when switched off manually on settings.I took the phone back to the cell c at lakeside mall in Benoni on the 25th October and it got booked in... during this time they are refusing to give me a loan phone!I use my phone to travel to work,I do transactions on it!!!This is a huge inconvenience!!! Everytime when I go there they keep having excuses meanwhile the job card given to me indicates that I should have been given a loan phone!!!the second installment went off yesterday!So basically I'm paying for a phone I can't use and will forfeit the data that I have paid for since I do not have an alternative phone!!!!I would cancel this whole contract if I could!!!I am beyond appalled by this matter!!!I cannot wait 14 business days without a phone for a phone I pay for!!!