The shop only works while you're standing on the house, but the movement keys still worked while it was open. So one nudge on WASD or the arrows walked you off without closing it, and from that moment every purchase silently did nothing. No message, no sound. Easy to hit and impossible to work out on your own.
It closes itself now when you step away, so it can't go dead on you like that again. Already in the latest build. which now is live and fixed.
If you're still on the old one: walk back onto the house and it'll start working again.
i hope that fixes your problem.