Wow, not cool.
If it wasn't for sale, don't tell me we have a deal and give me payment information. You changed the terms to be "first payed, first served" after saying we have a deal.
3:09PM - I say that I'll buy it and request payment information.
3:50PM - I get confirmation that we have a deal and payment details.
6:05PM - Kit is suddenly "first payer is served"
8:21PM - Payment made
5:21AM - Refund Issued