MTN unsolicited spam calls and CPA non compliance

I received an unsolicited spam call on my Cellphone from MTN looking for my wife, I immediately asked where our details were obtained from as is your right thanks to the CPA. I then received the normal ******* about using a host of suppliers so I asked to be put through to someone who can answer my questions after being told they are 100% compliant. I was promised a response with the details I requested and promised to be removed from their marketing database. I then received another unsolicited spam call from MTN and when I asked where my details were obtained from I received the same ******* answer and then the phone was put down in my ear.