What do i do if people broke my iphone?

Ok, so i got steam into my iphone a few weeks back and i think i've pretty much broken the hardware. It started off saying that there was no sim detected and then it said connect to itunes etc to do a restore but it didn't work. My dad took it to a small private shop that unlocks iphones today but apparently it was really dodgy because they said to come back and collect in a few hours. They said if they could fix it, it would cost £35. My mum collected it and she said the people looked really dodgy and they said they couldnt do anything but didn't charge us anything. My parents suspected that they might of taken out some parts to keep or swapped things and obviously they have: most likely the battery because now its COMPLETELY dead. Not even a display saying to connect to itunes. I don't want people to tell me that i was stupid for getting steam into it in the first place or how stupid it was to leave it with the people. I have no insurance on it and i want to know if i can sue the people for taking parts because its a sneaky business theyve set up. Or do anything to compensate. Would like to bring in the police or whatever-i know it was my fault for breaking it, but the people should Definitely NOT BE CHEATING PEOPLE and i'm pretty sure its illegal.anything so the people are shut down or so i'm given some compensation as theyve stolen my parts. At the mo, not too sure what else they've done. Thanks for help

Added (1). Unfortunately i've had it for a bit over a year so no warranty.

Are you like your iphone

If it is less than a year old it will be under warrantee and you can take it to the apple store and they will give you a new one staright away. Just don't tell them that you know what caused the damage.
you need to book an appointment at the genius bar on the apple website before you go

Sue the hell out of em its their job to fix broken stuff so if the mess your stuff up its they're fault. And taking The parts from your phone get the police and that's. All I can say