Bb seized, can't powder coat?

I want to get my old frame powder coated black but can't remove the bottom bracket.
I've taken it to the local bike shop and they can't get remove it.
What's the beat alternative to powder coating if I can't get it out?

Sounds like a bit of a fail of a bike shop.
At our shop we will get it out. It might take a week's worth of labour that you'll pay us for but it'll come out.