Lack of stock and inaccurate leadtimes

I’m a student at New Bridge and we have an agreement with Wize books to order all of our prescribe textbooks through them. When I logged in with Wize books website with my student number they already list all of my prescribe textbooks BUT DON’T HAVE STOCK. I received one email to say it is delayed to the 6th of August, I then called them to find out how far my order is, they said it is delayed to the 18th of August. I called again and now it is delayed to the 28th of August. Now how should I be able to write my tests/assignments without a textbook when Wize books keep on pushing the delivery date? I don’t understand how they can collaborate with colleges, know exactly what text books students need, and still can’t deliver. Very unprofessional. Don’t relay on WizeBooks you will be disappointed and have extra stress on you, not knowing if you will have your textbooks before your assignments.