I tried to uninstall Microtonic (installed with Sonic Charge Installer). When I start Uninstall Sonic Charge Microtonic and click on "Continue", the program hangs (I need to "Force Quit" to quit the program).

I am using macOS 10.14.

Sorry, the current uninstallers work poorly in 10.14.

How long did you wait? There is a known problem in OS X since 10.13 with a system command that has become extremely slow. I've been trying to fix it for the next release, and I have been able to speed it up by four times or so, but it can still easily take a minute or so.

(We actually just patched the online installers for this problem. But it wasn't so easy to patch the uninstallers.)