I am not from US, so forgive my ignorance but why don't you issue proceedings for the recovery of the debt in the small claims courts shoehorn?
It may be adult business but it is still a business debt, and the issue here is TOS.
There is enough evidence to support your claim and it should therefore be an easy ruling on a point of law and a lot cleaner than engaging in tactics that could be construed as trying to damage the sponsor's business.
Once Judgment is attained you then have options to collect the money.
