Have a merchant, 2nd pos behind IOU - no idea how IOU possibly funded this guy without a bank verification - do they even do them?

Merchant doesn't use online banking.

I try to accommodate new iso and client through a 3rd-party bank verification phone call, which we don't like doing but it's an absolute last option.

US Bank says they don't accept 3rd-party verification calls over the phone, all verifications must be done through 3rd party Bank VOD

Has anyone experienced this? What exactly does it entail?