Arrogant and rude call Centre agents

This has been the umpteenth time that I receive phonecalls from the Metropolitan Life call Centre on several different numbers, looking for Batiswa. The call Centre agents speaks in Zulu and every time I tell them they have the wrong number they get extemely arrogant and blatantly rude to me. I have requested for them to remove my number from their system to no avail. I have tried calling back to speak to someone in management but the line never gets answered. I do not recommend them in any way, they are unprofessional and rude.