Not long ago, I made my regular visit to the ATMs at Santander, likely the biggest bank in Mexico, and owned by a conglomerate in Spain.
I asked for my usual 8000 pesos. The machine made all the right noises, except the sound of cash coming out. I got nada...zilch.
I decided before going postal I'd race home not far away and check online to see if any money had been debited from my account. Yup, every one of the 8000 pesos had a new home somewhere.
I roared back to the bank for a chat with with the manager. He spoke decent English.
I told him the problem, only to hear him laugh in the public area of the bank filled with his staff at open-area desks, and dozens of customers. He broadcast loudly a stupid gringo (that would be me) was trying to scam the bank out of 8000 pesos due to a failure of his ATM. He practically screamed their machines were limited to 5000 pesos per transaction, but I wanted 8000! I told him I commonly withdrew 8000, and he then got even more public support for his derision of me.
Well, what to do with a guy like that?
I asked him, in front of everyone, if he wanted to bet USD 20.00 ( about 400 pesos) that I had previously drawn 8000 pesos. He jumped at the opportunity to make a day's wages from a gringo, and we shook hands.
Back home to get my Santander ATM receipt from the day before. You guessed correctly...it was for 8000 pesos!
When I made it back to the bank he was in his office, with clear glass wall. I showed him the receipt.
In front of everyone, he produced a crisp $20.00.
I waived it like a flag all the way through the branch.
In about 6 months the 8000 pesos made it back to my dollar account, due to internal systems to prevent losses due to ATM malfunctions.