Car retained worse from repairs

REGISTRATION DL92ND GP<br> <br> my car went for repair at BMW Authobahn when i went to fetch i discovered that the back seats of the car was removed or st********** or vandalised, when i reported this problem, they claimed that i have handed in the car like that to them and even showed me pictures to which i had no idea when they took them. i want them to take responsibility and fix my car seats..<br> <br>