Recharging your AC's refrigerant is only called for if the unit is running low. And a tech who just does a pump-n-run and tells you your unit is now okay is NOT a tech you want working on your system. That seems to be a lesson you've already learned though so let's move on.
It sounds like you definitely have a leak, so you need a competent tech to come check things out, go around the unit with a sniffer and find the source of the problem. If it's piping it may be an easy fix, if it's in a coil that's likely to be a significant repair.
As to the coils, they probably do need cleaning and that's something you can do yourself. You don't have to shell out a bunch of money to a guy who's essentially just going to hose things off.
Dirty outdoor coils are a big problem, especially because the vast majority of homeowners never think to clean their AC coils. Air flow is everything in HVAC, and unlike the coils inside your house, there's no filter protecting the outdoor condenser coils.
You can get a lot done with just a garden hose and a spray nozzle.
NOTE: turn off power to the AC before beginning any of the following.
Point the hose nozzle squarely at the fins. Don't angle it. Back up so you don't hit them too hard, even a regular nozzle can bend fins and bent fins block air so DON'T DO THAT.
Spray squarely into the coils. Side to side, top to bottom. Get them all. Go all the way around the machine.
NOTE: I'm an HVAC pro and will usually take the condenser apart: remove the fan, remove any exterior panels, separate the layers if it's a two-layer coil (God I hate those) and really go to town, being careful to direct the spray away from any electrical connections. There's nothing really difficult about doing this step but I don't generally recommend to most folks on Y!A because there's often a lack of experience or aptitude. If you're mechanically inclined it's not hard to do and will yield a better result because with the top and panels off, you can spray from the inside out, against the direction from which the dirt was sucked in in the first place.
In extreme cases you can use a pressure washer but I STRONGLY recommend you not use a pressure washer if this is your first time. You can pretty much a destroy an AC system in minutes if you're not careful. You need a low-power washer and some sense of how fragile the fins are.
NOTE: certain newer AC systems, equipped with "micro fin" coils, are actually fairly robust and respond very well to pressure washer cleaning.
Good luck with it. And get a better tech to work on your system.