Sometimes for unfixable issues or for stuff they do not really want users to know about they move to different categories or just delete postings. I would look for the past articles and try any troubleshooting mentioned in them. Be sure to clear all browser history data and cookies as with ebay this can help. Also check to see if there is a newer version of your browser and make sure your pc is up to date. If the issue has not been resolved by now then you may need to use a different browser. Edge and Chrome are working better than IE and FF right now and there has been some talk about ebay not fixing issues right away due to the browsers being older and too expensive to write fixes for. IF you are on a older pc the real issue may be that Microsoft is not writing updates regularly or has stopped supporting the os and browser. They currently are on edge and to prevent more issues it may be time upgrade your os or purchase a newer pc. The benefit with a newer pc is more storage space, more ram ,and a higher processor speed which will improve every thing. Plus if you are on a older os that is getting limited or no support you will have a greater security risk so since you are making purchases online to protect your identity and bank info a change will help protect you for a long time.
