Sound Stollen while service

On 06 January 2016 I had my Tata Manza INI at this branch. I took it in the afternoon before because I have to be at work early the morning. When I got my car back my sound system that was in the boot was ******. All they say if I phone is that they spoke to the technician and he said the wires where cut when he got the car, but the fact is the wires where never cut they where loosen neatly.