Remote sharing of the screen of a phone or tablet is possible using 'TeamViewer QuickSupport' app.  No remote connection can be made to your phone until you send the ID link, so unintended connections are not possible.

Search your Apple App Store or Google Play Store and install the app.

The app will create an ID.  Tap on the 'Send your ID' button and email it to help@incisivesupport.com

This app only allows us to view your screen.  As we cannot control it you will need to show the problem while we watch.