Poor service received

I have ordered a book. This is the second time. Only to be informed the book is no longer available. I have placed an order on the 31st July 2023. I received part of my order on the 18th August 2023. I send a request about where is the book that I have ordered and received a response my order was delivered. Yes I know, but only part was delivered. So I send a request again. Only to be informed the book is out of stock, not to be refilled again. I can get a voucher or refund.Still waiting. Why not just show the book is out of stock before you order?