Vodacom Poor,poor,poor service delivery

The service received form vodacom has been a total nightmare.Nobody is taking any responsibility nor accountability for the poor service provided,it’s been almost a month being pushed from pillar to post with no solutions,just more problems and being inconvenienced and nobody phones back when they promised to do so. I was incorrectly debited on my account for service,yet it was poor service,and my account being in a minus balance which vodacom has to take responsibility for it. If anybody can explain to me the difference between a month to month subscription and a 12 month contract,please cause clearly my understanding is completely different to what vodacom’s understanding is. I am so frustrated and angry and utterly disgusted with vodacom.