I would call.... but where I live it is impossible to make a phone call from my Vodacom phone!

I cannot make a call from my home in Muckleneuk Pretoria from my Vodacom phone. Firstly the quality is so bad that you cannot hear a word (yet you pay as if you do), secondly, there is a 98% chance that if you this call is longer than 2 minutes, that the call will either fail or become so bad that you have to retry. How is this possible in this day and age? Can this be addressed - who must I make an appointment with to assist (cannot call them unfortunately), if it cannot be addressed or there is no intention to address it, just tell me that as well, then I will try to find an alternative service provider. Thank you