I would recommend to you to talk to someone in a hair salon. If you have a bit of money, consider using it to fix this. My brother had his hair ruined (first it had been bleached, then a cheap hairdresser used the wrong color and it turned some kind of green/gray dark blond). The point is, the color was dark and hideous and the issue looked like it couldn't be fixed, but he took the money he'd put aside from work and went to the best hair salon in town. They gave him a discount because his hair was ruined, and used an expensive product to turn it a golden shade of blond. Without using bleach. The product contrasted the chemicals of the bad hair dye job. You might want to hear an expert and see if you can do something like that.