Has anyone have problems with there A/C?

Just 4 years old and my a/c is not blowing cold already!

Not sure what's the problem but I seen a leak on the firewall area next to the expansion valve, leak was green in color.

Didn't see any leak in the cab area so I'm hoping that this is the fix for my problem.

Truck in the shop this week for the repair of the expansion valve and re-charge.

Did anyone had this problem??