You may find the answer is completely different that what you assume to be the problem. The problem from your perspective is that you arrive and there is no availability. To a provider they see that every table in the house /room in the hotel is booked, as far as a business problem it is a good problems to have. Most companies over-allocate allotment, for various reasons and deal with the good problem to have rather than under-allocate and deal with threatening business problems. Historically overallocation is the only way to account for things like cancellations and no-shows. Fixing the problem may not be in the providers interest, making it in the providers interest is the issue that you have to solve for.