national tyres oil change balls up

got a call from a friend 2day, he was on the expressway when the oil light came on in his audi a6 1.9tdi,

so he pulled over, gave the guys at the national tyres a ring & said that he had his car with them for an oil change a few days ago & now the light is on,

so the boss came out to his car & what did they find :rolleyes:

a shinny sump plug resting on his undertray :shock: :shock: :shock:

yep when he spoke to the boss he said he had the yts lads do the oil change

they even forced the bonnet closed as they had left a screwdriver on the landing pannel :shock:

he refilled his car with oil & then carried on to drive to yorkshire,

so where does he stand now? his engine has run with no oil in what damage has happened there then, what happens in a couple of months if the engine seizes??