Also - don’t be soured on future purchases.
The situation you’ve encountered is the exception not the norm.
But feel free to be soured on individual sellers and buyers. It sucks if someone intentionally screws you, especially if it's for hundreds or thousands of dollars.
If anything, chippers should LOVE when they're screwed out of a couple bucks or a purchase/sale here and there. It's a cheap lesson on who to never deal with again.
*edit to say - this site and hobby is built to be this way. Thread crapping is not allowed, and if you call out folks publicly, like in a thread like this, you'll build a reputation and realistically you'll look like the one who is difficult to deal with. So there's very little public information on buyers or sellers outside of meaningless feedback ratings. That being said, there are known folks on here who live only to make a penny, and while people will still deal with them, they absolutely are not looked upon fondly. Just takes time, experience, and deals to figure it all out.