Deleting items from cart. Cant check out

Been trying to place an order for over 2 hours!!! Every time I check out it keeps taking items out of my cart saying no longer available til 20 or so items are gone. Then I have to see what I'm missing and I can add them back in. I keep Doing this over and over! I even Tried only buying a few items- nothing works. Soooo frustrated!!!!!