The easiest way is to join the support server and ask for help. The bot devs are there a few hours every day, and always ready to help you.
You can contact the ManageBot support by mailing email@example.com. It will take a few hours or days until you get a response, spamming will result in being ignored.
Not mentioned in the features, but still here: the integrated support system. You can directly message the main developer of ManageBot by using the integrated support system. To start, you can use
/support chat info and learn how to use the support system.