Don't give "legal advice" any more. Happily retired.
On the "practical advice" front, situation is likely this.
1. Check who your contract is with, and which law it is subject to (probably English, but might be French)
2. Check what sort of Card you made payment with. It it was a Credit (as opposed to Debit) Card, you will also have rights against the credit card company via s.75 of the Consumer Credit Act (provided the price paid was between £100-30,000)-at least, those were the numbers when my knowledge was up to date
3. Reason for 2 above is that Credit Card Companies are a whole lot easier to deal with than Suppliers. Not least cos they know they can bully the suppliers
4. On the assumption it is English Law, you are not obliged to accept a voucher. There is a clear breach of contract/failure to provide a service you had paid for. They need to be refunding the difference between the price of the service you paid for, and the one they actually supplied
5. Trick is to ensure that the supplier knows both that you won't be fobbed off and that you will cause them more administrative cost on arguing than paying
On a separate note, Gill looks very happy. Dies she have a hearing aid that she can surreptitiously turn off?
I asked Gill, & she said she used a Credit Card.
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