Impact meter box units chows electricity more that the bill system that is clear that the is something defiantly wrong there!!

Just registered with impact meter (apartment in wonderpark estate) I have a prepaid box that runs like water, when I requested for them to come and check it, was told I need to pay r600. What if I pay so much amount for them to just come and say nothing is wrong, then I requested to change to Bill answer was I can only change to Bill after a year. What the hell!! Really now.....? Now I must be stuck with something that will suck me dry ?