Edit: they've fixed this now.

I'm not joking, click on it and try to pay. It shows an invoice of ($5,000), a.k.a. $5000 negative dollars. I didn't enter real payment information to see what happens next because of really idiotic interpretations of what constitutes "hacking", but it is a really bad design choice on their part that took me about half a second to find.

Founder, if you're reading this: was this an in-house build or did you outsource this?

The answer is probably they spent around two days building this before demand grew left them zero time to improve infrastructure. Which is more or less good.

Less good? Infrastructure breaking because of load is one thing (concurrency/DB issues) but nothing like this should ever be exposed to the user on general principle.