Is there a dye or somewhere I can send my 2 seater polyester canopy to return it to its' original black?

my lovely 2 seater swing seat has a black polyester canopy. The underside is still a lovely black but the top has gone a terrible grey in the sunlight. I tried Dylon machine dye but it didn't touch it. Is there somewhere I can send it to get it re-done or a simple way I can do it myself?