That doesn't happen. They did have a computer system break down once, but they have a backup system. Visa and MasterCard process 3,000 transactions a second. There are mistakes and some fraud. But they find out about it and usually fix it quickly.
Government is slow to fix things.
It's slow about so much. As Lynn Sherr reported, some polling places use voting machines almost half a century old. Government's inability to modernize is routine. That's the reason for those horrible delays at the airports. So much for that trip.