I hear ya! Every penny counts. I hate it when people say"you get what you pay for" when it comes to body work.
A true professional would make things right. I am sorry you are dissatisfied with the finished product. You might wish to express this in the form of a placard at car shows,stating who did the paint and bodywork. No insults or inuendo,just the name of the person or shop involved. When you asked about it,express your "opinion"!
I would color sand the overspray off. It's the safest way. Take your time,dont sand too much or you will break through the clearcoat. Use very fine paper,maybe 1500 grit or better and lightly sand it.Use no hand pressure,let the paper and sanding block do the work. This will make it easier to hand polish out
Fill a 5 gallon pail with warm water and ad some liquid dish soap to it. Use this to lubricate you paper by dropping all your wet/dry sandpaper in it.
If you drop any sandpaper on the ground, wash it or discard it. Any grit will leave deep scratches.
Use a constant supply of water while sanding to flush away any material. I like to use a light trickle from a hose,but some use a mister bottle.
Be patient.
Wash the vehicle when done.Make sure it is spotless,so hand dry it with something lint free. Then polish it out.
Power buffing is best left to a pro if you have never done it. It's real easy to burn a hole through the paint.