Unwanted calls and staff who do not know what they are doing

where do I start? with POPIA, how did they get my contact details? secondly when I question the call center staff, they either drop the call or leave me hanging on the phone. I have asked my switchboard to block the numbers so that they do not contact me on my work line but obliviously, they keep changing the outbound dialing numbers. the supervisor on duty is obliviously acting dumb on purpose when I questioned him earlier today as I did ask for emails from the company. If it it not sent on black and white, then I am not dealing with you. end of story