Brand asked for a blogger list

Business risks

If you hope you're going to get a sale after you dropped a list to your client without a prepayment you're an idiot. If prospect's affiliate manager wants to ensure you're not scam and won't begin looking for these bloggers after the first payment he might request one or 2, but not a list.

Solution

They want lists give them exactly what they want for money, if they don't need it they won't buy.

You could call them tirekickers, but unfortunately not people are comfortable with saying no, and just prefer to keep doors open.