Telkom breach of POPIA

I am a Telkom customer for cellphone services. I and my wife get marketing calls multiple times a day and several days a week. We block their telemarketing number, have registered with telkom not to call us, yet Telkom staf at their shop say they can do nothing to stop these calls. This is clearly a breach of POPIA. Is anyone else having these problems and can we take up a class action against Telkom so they do follow POPIA and stop harassing their clients.