The Seller and Feedback links in the image below do not work in narrow viewports...
In wider viewports all the links do is scroll the screen to bring the Meet The Seller section into view - from where buttons can be used to access detailed Seller and Feedback information.
In narrow viewports the Meet The Seller section is not being displayed on the page, so the links have nowhere to go. All that happens when the links are clicked is that the screen jumps about one line.
The links would be far better going direct to the seller's About Me and Feedback pages.