On the first page of the fax we wrote all 6 paypal accounts of our partners + all the URLs at _their sites_ where they show link to the sale.
Surely, the 6 vendors won't point to a pirate selling web site, right? Also, we provided all their 6 paypal accounts. They could just call them to verify (which they apparently did when processing limitations of my partner's account).
Jacob. Apparent Software.