4 unlimited contracts but no signal for months

I am very very unhappy with cell c first of all we went to cell c head office we bought 4 buy out deals the unlimited corporate deal we struggled for a week just to get the phones after we got the phones we have struggled for to weeks just to get the phones activated and after that we have struggled again for about 3 weeks to get paid because the said its corporate so they can't give us the cards the have to pay the R40 000 into the acc after that the hole thing was sorted an every one was happy we have called cell c multiple times regarding the signal at the office we have absolutely no signal at our premises we had to take out a vodacom contract just to be able to call clients again its 5 months now and we are still trying to get them out to do something to the signal but when we call them they say they working on it but its 5 months already i am on the point to cancel the contract because i cant see the point in paying R6300 per month but have limited access to signal i have got the to the poiny of coming out 2 my premises and i was promised that they were going 2 install a antenna but that was 2 months ago