When I make my deposit, besides the email from pokerstars, I got an email about my transaction from myspeeddebit.com.

I assumed they probably process the echecks for stars, and so the bank deals with them. I have nothing at all to back that up, but it made sense when I thought of it.

On my banks end it appeared as "TIGRASUPPORT EFT".

Whatever it is, they don't appear to be dealing with the site directly.