Can't make a simple phone call from my office

I have phoned Vodacom multiple times, had them come out here to see what the problem is and install signal boosters. <br> Even with the new booster, I still have to go out of my office to take or make calls on my cellphone. <br> They keep promising to look into it, but that seems to be where it stops. So far nobody has taken any action to resolve my problem.