Another trick I use to avoid this is to put some twist ties tight around the frame in a few places so the bag rests up against them and not your frame. Using a hard mount works best, made one myself based on input from fine folks here...
I take good care of my bike, but I don't sweat every little scratch...ride safe.

 

I put a Harley bag on my swing arm 2 years ago using 2 zip ties per slot (6 total) and put 2" pieces of a paint stir stick to reinforce the inside of the bag so the zip ties wouldn't tear through the bag. The zip ties keep the bag firmly mounted and so far no complaints. I'll worry about the minor scuffing when the time comes.

 

Why take it off now the damage is done? You obviously liked having a bag and the way it looked or it wouldn't have been on long enough to rub the powder coating. Don't be so sensitive

 

That sound like a good idea.

 

Without pics it might be hard to understand, but it works....even 3 years later. I'd do it the same way next time.