Signal is no where to be found

As a Cell c client who pays R600+ a month on a contract I find it a waste of my time and money as there is never any signal so why pay for a phone when you are unable to use the phone due to no signal?? Funny part is you have a store less than 5km from my house selling Cell C deals in Woodlands shopping centre Pretoria but outside the centre you get no signal!! You guys need to seriously fix this problem or come to my house and put a booster in because I'm tired of not even being able to utilize my phone or even WhatsApp out of all things. So can you guys help ASAP!!!