Help Reviving a synthetic wig!

I’ve bought a second hand wig from vinted, it’s just arrived and it is in a disgusting condition. It stinks and looks and feels greasy, the same way unwashed natural hair can appear. The ends are dry and frizzy and looks as though too much heat has been used on it.

Any advice on how to rescue this. I really don’t want to have to throw it away, I’ve wanted this particular wig for ages and the original seller no longer sell this particular one anymore.