No spray paint really lasts. I imagine the paint they use at the factory is some kind of epoxy or catalyzed paint.

You *can* get small quantities of single stage automotive paint and brush it on or use an automotive touch up aerosol sprayer but you also need reducer and hardener plus a proper respirator rated for auto paint - catalyzed paint is extremely toxic. I suggest spraying outdoors as well - which you wouldn't want to do with a car but it's not like you're trying to do a nice auto finish. The smallest quantity you can get is going to be way more than you need.

Another option is boat paint - not as toxic as auto paint and it's tough.

With any paint surface prep is important.