You're just playing with words now. It's not "proving a negative" at all.
If one claims that EESO is not making any revenue, then that is just as much a positive statement as it is a negative statement. To claim they have no revenue, it is assumed that you have prior knowledge of the revenue, and that is the basis on which you make your claim. You are then making a positive claim, that "the revenue is zero".
Only two questions are relevant to this discussion then:
Exactly, how much revenue is EESO earning?
And where is your proof of this?