Takealot Unacceptable Return Policy

I am very disappointed with takealot. First i believe that they should check their stock before it leaves their warehouses so that they make use that i/ a customer receives what they have paid for. That being said i think i know that human error happens but the turn around time that they have to fix that error is really unacceptable. When you buy something from them online, they will give you options on how long you want your product to be delivered to you. The shorter the period the more you pay for the product to be delivered fast to you so my question is cause now that they delivered the wrong thing/ incomplete product why don't they use the some policy to get me my things fast on their account? why do i have to wait a week to get what i have paid for and they didn't check before they deliver that it is the right thing?

The process they use is unacceptable and will make not buy anything from them.