There are a lot of negative reviews aimed at the developer because of the lack of screen sharing and control. This is a result of Apples restrictions and isnt something TeamViewer or any other similar app can get around.
The most they could do is explicitly state in their app description that it doesnt do screen sharing or control due to iOS restrictions.
The person calling the developers scum because this free app doesnt let them work with their IT department is out of line.
EX13520 about TeamViewer QuickSupport, v11.0.67984