Plastic isnt working

the plastic is probably already reserved for some other building

There was none other building to use that plastic, but after i gave power to the polymer press the game let the Oxylite Refinery be available, thanks for the fast reply anyway SGT_Imalas !!!

Also, you do not appear to have 800kg of copper, gold, iron, OR lead. The tooltip doesn’t specify which resource you are short on (refined metal or plastic), but I think you are short on the refined metal.

This is doesn't look like a bug, if you don't have not enough refined metal, you can't build it. Try building a mini pump which uses plastic and check if it works!