[christkv]

If they believe the claim to be false they can open the data they used to calculate the 5% so it can be verified by a third party.

[berkut]

So you want them to publicly list / make download-able any phone numbers of the people in that 5%, and their full names and email addresses?

[ahahahahah]

Absolutely not. No social media company should take a set of user's private data and "open the data" (especially just because some blowhard is trying to find any reason to back out of a deal). Even without the "open" bit, they shouldn't be providing that data to a third party.