I've been with Netstar for a long time

I've been with Netstar for a long time. But unfortunately I am UNSATISFIED with them. My Netstar unit was draining my cars battery. I contacted Netstar and told them about it. Where upon they informed me that if my battery was faulty they would charge me for a call out fee. I have had my battery checked before they came out by 5 different battery centers and there is nothing wrong with the battery. However Netstar charged me for a call out fee of R1500. I contacted then finance department, And now I'm waiting for a response from them.. Sent emails and still nothing. I'm totally disappointed and disgusted