The problem comes from what you post under something that's not your name.

Personally, I'm thinking perhaps the answer is the other way around:

Any company that collects data apart from what you directly provide them must make a best-effort to end you an e-mail every year with the data in a standardized format or links to the data. (Doesn't need to be burdensome--documents go behind a UUID with a non-readable directory. You either know the URL or you don't.)

You have data you didn't disclose, pay $1 per item + costs. (If you have useful amounts of data that per item will add up really fast.)