Problem with Safari when shopping online

I'm having problems with Safari when I want to pay for things I buy. It completely freezes then scrolls for hours when I click Pay Now. Also, I want to sell something on eBay but it just goes to a blank page. I have checked with Chrome and I have no problems selling or buying there.

I'm wondering if this is a software issue and whether anyone on here has experienced similar issues. I've uploaded a screenshot of About This Mac and the Safari version I'm using so you know what I'm working with.

TIA

[Edited by Moderator]