wrong billing

Poor client service, I was advised by the Netstar representative last month (August) that my 3 years contract with them is about to expire on the 17 of September 2022 and I agreed to continue using my old device fitted on the vehicle.

She told me that monthly premium will be R150 and I agreed to be debited on the 15th monthly. surprisingly Nestar debited my account on the 1st of September and the amount is double on what we agreed upon. I tried several times to call them, they keep on transferring my calls and hang up I don't get an explanation.