Misleading delivery lead time

Can you explain how does a next day delivery turn to a next week delivery???

This is completely annoying and frustrating from Amazon - I never order from them and this is like the second or 3rd time I am ordering and it clearly does not inspire me to consider them for the future. I was going to order the same thing from Takealot and ended up with Amazon because they promised next day delivery but that never happened and when I went on their app to track the delivery, it has now moved to next week. This is annoying and not professional.