debit order mistake

After I saw a mistake on my bank account, I contacted direct axis. They checked and let me know on Thursday that they had made a mistake and would pay the money back into my account. NOW ONLY, do they suddenly mention that a refund takes 10 days. Oh wait, ten WORKING DAYS. What am I meant to do in the meantime? It was their mistake. I had no problem with it, as obviously mistakes happen. But now they expect me to wait so long when I have other payments I need to make? That is completely unacceptable.