Nintendo Switch left Joy Con Fix?

My switch has a problem with the left Joy Con.

The left Joy Con is no longer handheld. I've already tried by a friend the left Joy Con on my console, did not work either. It must therefore be the recognition part. Can anyone help me?

Maybe clean the contacts with alcohol.

Could be, how? Where are the contacts anyway?

I also had some problems with the Joycons. I sent my Joycons to repair Gamestop and have not had any problems since then. It cost 60 euro but the price was definitely worth it

Can I fix my Gamecard slot?

Yes, but that will take some time. I had to wait 10 days to pick her up again