I think if it were only a matter of taking a long time to delete the account, we wouldn't be so unhappy. To me, the reason your team's behavior seems extremely unprofessional are

1. Not telling Liza when her account would be deleted

2. Telling her her account was deleted but not actually deleting it

3. Sending the "Do you and your friends want to disturb us with this" email

4. Editing Liza's account to claim that she was banned for spamming