I use my United Airlines Credit Card for my business expenses to earn air travel miles. I had an order from a client that I put on my CC for $3500. A couple of weeks later, this client called and wanted to postpone the project until July. I can’t carry that much debt, so I called the company I ordered from and cancelled. They refunded the money back to my CC account.
Is United going to take my miles back? They have already credited the miles from this transaction to my account.
Why don’t you call the credit card company?
Yep, they will claw back the miles on your next statement (or maybe the one after.)
Most likely yes. Otherwise there’d be an easy way to fool the system in order to get tons of miles (and, with these miles, flights) for free. They can’t allow this.
Of course, the bank that issued the credit card pays United for those miles.
But if by any chance they don’t, let me know, cause I want that CC.
I’d be stunned if they didn’t remove the miles from that purchase from your account.
Small sidebar: when the airlines first started issuing credit cards on which you could earn frequent-flyer miles, people very quickly figured out a way to use those cards to generate large quantities of miles. They would use the card to buy a large sum of traveler’s checks (back when those were a thing), then use the traveler’s checks to pay off the balance on the credit card. The airlines quickly realized that this was, in effect, giving away free miles, and they changed the rules on their cards.
People are still coming up with manufactured spending schemes to this day, though they get more complicated as more and more avenues get shut down.
My friend (really! 
) used to move over $50,000 a month through various SkyMiles cards through various schemes involving buying prepaid debit cards.