That's not a bitcoin question, that's a per-exchange question. If an exchange gives users an SLA stating "orders will be fulfilled within X business hours" the

That's not a bitcoin question, that's a per-exchange question. If an exchange gives users an SLA stating "orders will be fulfilled within X business hours" then that's a contract between two parties. If the exchange says "yeah, we'll get around to it someday and you agree to deal with that" which is the usual intent language in the small print then you don't have much to go on if there is a delay, other than trying to raise a public outcry in the hopes they will back down.