Our firm actually deals with ESS as a client.  Yes, we have had some recent issues with payment.  And I would agree the mailing address is a far cry from their office "location" after speaking with them.

 We do not conduct much business with them, however, in the future if we have any more payment issues, we will not do any business with ESS.  Recently their check issued for services rendered bounced.  Our firm was obviously charged a returned check fee.  We re-billed them and included the fee we incurred, and after numerous attempts for the returned check fee---nothing.  We did get our original payment eventually.