Sharing/selling privacy information

I bought a vehicle on We buy cars auction. They send me forms to fill in, the privacy consent forms was pre-filled in with the customer giving consent to share personal information. I scratched it out, and made a note to prohibit wbc from sharing any of my information to anybody. Next day I received one call from nexstar, one call from outsurance and three calls from people selling maintenance insurance. WBC are in contravention of the popia act, and I have already started procedures against them with the act and the constitutional law on privacy.