Rich is right on the money with the surface prep.
I still use the Tamiya paints with no problems . I get mine off EBay or Amazon. I haven't used the Model Master paints . I'm sure there are different quality paints that forum members use.
When I paint directly on plastic parts I use Zippo lighter fluid to wipe the area . Zippo leaves no residue and doesn't melt the surface of plastic . Plastic contains oils and when the surface is wiped with the Zippo it sort of frees that area of the oily chemicals.
I actually use Acetone when prepping the surface for gluing only ( not painting ) since it will begin melting plastic. 😨
