I've been blocked by fraud protection when trying to buy pet food at a pet store next to my house, trying to buy fast food while visiting a friend in another city, trying to buy two cell phones in one day because the first one was out of stock and was refunded, trying to buy software from any company headquartered in another country, trying to buy crypto, trying to buy health supplements from a friend's company.

Supposedly, when they suspect fraud, you get an automated call where you can indicate a charge is legitimate and they'll let it go through, but I rarely got a call, and when I did, purchases that I marked as legitimate still wouldn't go through.

I talked to a real person with the fraud department, and she had no idea why the charges were being blocked, since, according to her, they should't have been. But also, there was nothing they could do about it.