To completely unintall the addin:

1. Go to uninstall programs and uninstall anything that is related to the addin

2. Go to ms outlook remove the addin via Options -> Addins -> Com Addins

3. Go to program files x86 or wherever it is stored and make sure Spamtitan folder is gone

Then we need to go to the registry HKEY YSERS -> FOLDER -> SOFTWARE -> MICROSOFT -> OFFICE -> OUTLOOK -> ADDINS

and remove any Spamtitan addin entries

This should completely remove the add in.