Was the problem sudden or slowly getting worse?

Years ago I had a customer with a Buick that suddenly stopped taking fuel, turns out there was a gas pump certification sticker blocking the fuel fill roll over valve. ( the sticker was folded to fit in the gas nozzle and they were the next unlucky customer. )

Fuel flows in the large hose and air out the small hose. When the tank is full, fuel burps up the small hose triggering the shut off. If either hose is blocked, fuel will backup and trigger the nozzle.

Does your area have special gas pump vapor recovery systems?