Carcraft has apologised to a customer after mistakenly handing her Mini out as a courtesy car.
The debacle started after Joanne Bardhi took her vehicle in to the car supermarket's Bootle site in Merseyside for an MoT, reports the Liverpool Echo.
However staff only realised their mistake when Miss Bardhi asked for her keys back.
Efforts were quickly made to contact the driver of her car who it transpired had driven to Shropshire.
Miss Bardhi was given a genuine courtesy car while her vehicle was tracked down.
Bardhi, who missed a day's work at a hairdressing college while the mistake was sorted, said it was only when she calmed down she realised her house keys were on the car's keyring and there was a letter with her address in the vehicle.
Carcraft's marketing director Julie Phipps apologised to Miss Bardhi and offered to pay her £500 compensation and change the locks on her house.
Phipps said: "We are extremely sorry for the inconvenience and upset caused by this error.
"We have thorough procedures in place which cover courtesy cars and it is apparaent these were not followed in this case.
"A full investigation is now being undertaken and disciplinary action will now result."