What page is it switching to?
Are you using a browser or the app?
If you are using a mobile device, there is a setting that can cause eBay browser links to open in the app by default. If that is what is happening, there are ways to disable that, depending on whether you are using Android or iOS.
Try a browser, or a different browser, to see if that makes any difference.
If you are using a desktop browser, your cart should be here:
https://cart.ebay.com/
