Using my number as emergency contact for someone else's account

They have my contact details as an emergency contact for some motor dealership in Johannesburg and it is IMPOSSIBLE to get someone to remove my details. I get calls EVERY day when any of the batteries get disconnected. I have already submitted various complaints in writing, I have spoken to about 12 "supervisors" and no one has been able to fix this. The only option left would be to cancel my subscription and block their number.