Category pagination (if thats what its called)

Hi,

On any of my category pages when clicking page 2 they are not showing the correct posts, my posts/products are set to show by price which works fine on page 1 but then if you click page two you start to see the problem that is occurring.

Here is an example of my post categories:
https://www.mrbusinesscards.co.uk/business-cards/1-sided-single-business-card-printing/

I really need this fixing as my products that don’t make page 1 don’t get seen because of the issue.