How to stop the paint from scratching off.
Hi, I dont know if you got the paint problem solved yet, but I'll let you know where you went wrong in prepping plastic for paint. Peroxide will not clean anything other than a cut ... it will probably leave a residue behind that is preventing your paint from bonding. Wash the plastic with dish washing soap first to remove any oils or dirt, then wear gloves so you dont get your finger prints on it. Finally give it a wipe down with rubbing alcohol before you paint. This shold give you the best possible adhesion.
Hope this helps.