garage has kerbed my AMG's very badly!!!!!

[strictlyVAG]

was washing the car yesterday for the first time in a month and noticed the front passager side wheel was muddy, after the mud jet washed off so did half the paint revealing a good 6inch long rough chewed up edge of the rim,

now 3 of the 4 rims are marked anyway except the passenger side rear, until now! what ever has gone along the front has also clipped the back,

i know it wasnt me that did it and all the previous marks have been filed down slightly but these are that bad they cant be!

i went back to the garage today but of course they denied it,

where do i stand?