Help on a situation of a 2 weeks fee!!!

[snuggles]

My sister has a daycare and ask me for advice but not too sure about what to tell her, so I though of this site.

She signed with a couple and held their spot with a HOLDING FEE DEPOSIT which is 2 weeks of care, which is on the contract (holding fee contract, not contract of child care) which will go towards her first two weeks of care of the child- but non-refundable if they decide not to put their child in her care. As holding a spot for 5 months without income and refusing other potiential clients, which is also written on that contract.
But when she started with the child, she had a terrible first day and the parents were pretty rude with her and so decided to let them know that same day, it won't work out and they need to find alternate care until they find a suitable provider..she then felt bad and said she may bring the child for the two weeks to give them time to find another daycare, they refused.
They then send her an email asking for their full deposit ( which was a holding fee not a deposit) my sister says that it's was her security fee since she losted 5 months of income holding this spot which is a 3 day a week. She also said she'd give it another try since it was a spure of the moment notice but they refuse again.
They're saying she didn't give two weeks notice and they expect to get their full weeks deposit- which my sister think she shouldn't because it was a holding fee, but it says it will go towards their first two weeks of care:S
but she did offer for her to return for the rest of the remaining days and also offered to give it another try! Any help or advice would be great

She though of giving half of the holding fee/ or give it back but keep one day as she cared for the child.