Topic: stripping electroless nickel

I had A-2 tool steel parts with eletroless nickle on them annealed and the re heat treated. I now have plating in some of the tapped holes. The plater tried to strip but said the stripper would't touch it.

Is it because they were re heat treated with the plating on/ Did this do something to the plating/ if so what can I do to get it out of the tapped holes?