Vodacom - Airtime Subs - RED Flexi 65 Line Rental Cancellation

Transferred my contract in January 2020 completing all the necessary paperwork at a Vodacom shop, but billing continued for the line rental of an additional benefit included as part of the contract i.e. another number and sim. This billing took effect after the contract expired in November 2020.

Tried twice by calling customer care to cancel this line rental, twice paid arrears amount not due and most recently in December was called almost daily about an arrears balance threatening to black list me over a +- R350 alleged outstanding amount. Billing stopped in August 2021 but now has started up again in Dec 2021 and Jan 2022.

Vodacom appears not interested in cancelling this line rental and I don't know how to get it stopped. Been a customer on a high end usage plan 20 odd years. Incredible to treated like this.