Vodacom not delivering (signal) and service!

I'm dropping about every second call that I'm making and then my phone keeps on ticking over even more seconds that I'm paying for - without being able to use the line during that time! I've informed Vodacom of this problem a very long time ago after which they requested that I go into one of their shops for them to have a look at my phone and it's settings - which I did but the problem persisted. Then they looked at my simcard but noted that that is also not the problem. In the meantime I requested that they then at least rectify my large bills as I'm paying for a service that they're not delivering! This was \escalated"";only to be ignored by Vodacom once again! I've lately also spoken to many other unhappy Vodacom clients who are also experiencing similar problems..."""