Still being charged for a cancelled contract! Poor, pathetic service!

We were contracted to Netstar since 2012. Cancelled the contract in August 2019, was still debited full amount till November 2019 and they are still debiting an amount of R36.04 till January 2020! We do not have the unit in our vehicle. Contacting *** for the past 30 minutes and I'm still on hold! Pathetic service!