Poor customer support

Good day

I have been overcharged on my August netstar bill. I canceled the netstar unit on my Ford Everest on the 13 July with effect from 15 July as I traded it in and took out a new unit on my new vehicle. The agent clearly told me that it was canceled. When I received my statement before the end of the month I noticed that the Ford everest was not canceled. I immediately contacted netstar and was told that it was canceled. Please refer to your recording software the calls to verify that I have canceled it. Kindly refund the extra amount that was charged for the Ford Everest immediately into my bank account. Kindly also note that the new unit is not working very well. It keeps showing my vehicle is still at work when I am at home and doesn't show the trip route properly on the app.

Kindly resolve both these issues with immediate effect.