So let me understand this...
An agreement on price is made...
Escrow.com is started by the seller...
Both parties are aware of the 12 hr time period to complete what??? At that point I am unclear on what a 12 hr period is in place for, it isn't a reasonable time frame for payment, transfer out etc, so again ??????
Your stories don't add up, someone is not being honest.
If in fact the seller agreed to sell and the buyer agreed to buy at a price of $XXXX and escrow was started by the seller, what was the issue?