You may want to post on one of the app discussion boards, and provide some additional details of what sort of issues you are having.
Also, if possible, mention your device type or model, the operating system version, the version number of the app you are using.
https://community.ebay.com/t5/Mobile-App-Android/bd-p/androidapp
https://community.ebay.com/t5/Mobile-App-iOS/bd-p/iosapp
Many common app issues can be addressed by signing out and signing back in, or uninstalling the eBay app, restarting your device, and then installing the latest version of the eBay app from either the Google Play Store or the App Store.
If you are using an Android phone and having problems getting the latest version of the eBay app, make sure you have the latest version of Google Play Services and Google Play Store:
https://support.google.com/googleplay/answer/9037938?hl=en
