No regulator will find any proof of anything though, as regular employees will not have access to such crucial data. Regulators will also can be fooled by the maze of interfaces and servers.
There is also incentive for governments to "not see" any wrongdoings of the companies, if they profit from surveillance system.
Ad business is like Palantir in lord of the rings. You do know know who is watching on the other side.
All you have is some "vague" promise from corporations that your data are properly removed.
e.g. what are 3 30 year olds in Toronto talking about this saturday? likely the drake concert, winter tires and xmas related things..