They're vinyl, but thats fine...
But, Yeah, unfortunatly, you'll have to strip it and repaint, if it came out sticky you probably painted while it was too cold out. It'll make the paint congeal (turn to jelly) before it cures, and after that it never will cure (dry completely), this is the main cause of stickiness
Or it may have been too humid, water content can effect the outcome.
Lastly, you dont need to use primer when using
krylon fusion for plastics, follow the directions on the back
exactly, no sanding, no priming...
just clean well using amonnia and water, dry, lay down a light coat, then follow with a full coat, and repeat coats about every 10 minutes
In my gallery here you can see a few of the things I've painted using krylon fusion
My Gallery