Scheduled Emails sending to the same list parameters!!!

This MUST get fixed. This is the SECOND time this has happened.

We schedule two emails, one with Selection Criteria A scheduled to be sent @3:00pm
and the other, with Criteria B, is scheduled to be sent at 6:00pm.

So they are scheduled 3 hours apart! And they are both sourcing the same MasterList.

But when they get sent they BOTH are sent to Criteria B!?!

I cannot begin explain how much this screwed up our customers.

What the heck guys. The first time this happened, I scheduled the email 15 minutes apart. When I contacted support they told me to add more time between the two sends. Apparently that is NOT the solution. 

I await a response, Thanks.