That's terrible @Emma2274 .
You are not alone in despairing of Airbnb's failure to uphold it's own policies, and will find hundreds of posts here in the CC relating to this if you use the search feature, top.
It's bad enough when those with a 'strict' policy report failure to receive their 50%, but your experience with the non-refundable has hit a new low! -Probably not the first time tho'...
Customer Service is known to have poorly trained operators, who appear to have been instructed to keep the guest happy, at the expense of the host, so many here will observe.
Welcome to the CC from a fellow resident of Cumbria! - Your place looks gorgeous, I couldn't think of a nicer place to be in (partial) lockdown! 🙂