How do I clip this back? Small clips broke

My 2004 G35 6MT coupe started having issues with the head unit and had to swap it for an Alpine radio, the guy at the shop that installed it seems to have broken the little tabs on the clips, most of the clips is there except what stops it from slipping out. Anyone knows how to get this back to its original state or how to fix the tabs or another way? Seems they also had dirty gloves while messing with it, how do I clean this felt like material? Any advice is much appreciated.