I know how frustrating it is when there's a technical issue making life annoying for you (or worse than annoying). As has been said, I'm not sure how much help any of us can be...

Have you tried accessing your account on another device? (For instance, if you're accessing it on your computer, have you tried accessing it on your smart phone or tablet/iPad?)

Have you tried accessing it on another computer?

Have you tried accessing it on, for instance, your ipad connected to a free Wi-Fi connection provided by a shopping centre? (I think even fast food places have free Wi-Fi as well.)

If any of those suggestions result in your being able to access eBay, then the problem might be able to be narrowed down. It could be your ISP; it could be your computer.

Can I also ask whether your browser is up to date? I'm supposing that it is, as you mentioned that you tried using other browsers - but just to be absolutely sure...

How old is your computer? What's the operating system? All of these things might have a part to play in this ongoing problem that you're having...