I recently had problems with a B&B booked through Bookings.com. The accommodation was paid up front to Bookings.com.
Once back home I complained to the company, who initially were most apologetic but informed me they had nothing to do with my complaint as they only act as intermediaries. They advised I take the matter up with the accommodation owners. The internet advert on Bookings site was misleading and just plain wrong.
It is my understanding that once money changes hands that a contract is said to exist. This is between buyer and person /s who originally receives the money.
Although bookings.com are HQ in Netherlands, they have an office in England, so I maintain that they are subject to SOGA & Consumer Protection Rules. They don't even think I am allowed to try & sue them in a Small Claims Court. In other words, like a well known major cut price retailer, they think they are not subject to UK law.
They have now stopped corresponding and say the matter is now closed. Even although I said we are waiting for medical evidence.