The only time I've ever botched a refund: I was so confident in one of my old refunders that I opened the package before the refund was completed. The store was patched while I was going through the process. Yes, the refunder failed it, but I could have still returned the item had I not opened it.
To answer your first question, I probably would put it into sports betting. with stocks and crypto I know everyone has to start somewhere...but personally I only like to put higher amounts into stocks and crypto (close to 1k or more) and if it was less, bet on some sports. thats just me. there are websites where you can place wagers using BTC