Nope, they were paying for the slot and you were available all week. I wouldn't refund. I notice you say they are struggling too, well then why did she quit her job? I understand you are friends which would possibly make this a tricky situation for you but I would not refund and I would also expect 2 weeks notice. It's not really fair of her to do this to you with no notice and then want her money back on top of it!

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