Vodacom does not believe the POPI act applies to them

Vodacom keeps on sharing my personal details with 3rd Parties (business partners). Whenever I do business I always opt out of additional marketing. However I am constantly contacted by people claiming to be from Vodacom for upgrades, extra insurance, ect. I tried to complain about it with the customer care line but they claimed it was their right to target me with telemarketing. I do not have the option to opt out (according to them)