Hello @AmonRa2017,
It is regrettable to hear that your friend is having issues with her chatbox. At this time, we do not offer email changes for chatgroups, so it seems unlikely that your chatgroup was put under the email of her friend, as you mention here:
If a main owner allows another main owner to be made, it is the original main owner's sole responsibility to ensure that the chat group is not taken over by the second main owner. Remember, you should only make your friends the "Owner" rank unless you absolutely trust them. If the secondary main owner refuses to give up access to the original chat group, I suggest unassigning all group powers from the chat and creating a new chat for free. Perhaps ban that user on your new chat, or make it members only.
If you have any other questions, please feel free to open a new support thread. This thread will now be locked.