When I press L2, the key goes down but does not go up by itself
I will be happy if you can help
Sony Dualshock 3 sixaxis
Here’s the ifixit DualShock 3 Trigger Buttons Replacement guide that may help.
If the button is faulty and needs to be replaced, replacements are available online (supplier example only to show cost of part). Just search for Dualshock 3 trigger button to get results for suppliers that suit you best.