Cartrack deducting money that I am not supposed to pay since I have a maintenance plan

I have been paying a maintenance fee on car track so that when the technicians have to come fix something on my bike, I won’t need to be charged an extra r600 call out fee for the service. In January, the technician came and had to change the device. Instead of only being charged the device money, they also charged me the call out fee and I have been calling for the past 2+ months for it to be corrected and they keep on saying they will return to me. Today I see they’ve deducted the money even though they did say I must just show they the proof that the technician didn’t come here and not find me…They haven’t gotten back to me and the accounts department is deducting the money coz the customer service people are not fixing the invoice. I am so mad, why was I asked to add the maintenance plan if it will not work? And how are they not treating my matter with urgency? I want my money back!