POOR SERVICE FROM ALTECH NETSTAR

I have 3 vehicles with Netstar After numerous emails and +10 minute calls and being transferred from pillar to post, I finally was put through to Retentions to cancel the one vehicle (LC01XTGP) on my profile as there was a re-installion doen from the old vehicle to the new one. On conclusion of the call, I was promised to received an sms confirming the cancellation and agreement of the discussion. Netstar can check and verify the discussions via their recordings of the calls to my number ***. ...but instead, I am receiving sms for legal handover of my matter and the vehicle that is no longer in my possession is still on my profile and I'm still being charged for it even though I have received confirmation of it being removed over and over on the calls referred to above. I don't know how to reach out to them to sort this out further and my patience is running very thin.