So I've ordered something on tmp and the price was 0.002 btc higher than what I had, I sent the money anyway, now the money isn't in my wallet anymore and the order has been cancelled, because I didn't pay enough How do i get my btc back? I still have the private key.
I would try messaging support and cross-posting this to /r/themarketplace. I'm sure /u/TMPSchultz or /u/MeImMrE could help you figure that out pretty quick. Good luck!