Sorry for the confusion.
The forgot password link that was provided to you before, it will ask for the TPG username or customer ID, right?
Instead of entering the main TPG username, have you tried to enter your slave username? If not, are you able to try it right now in order to receive a temporary password for your slave account.
You are right, the forgot password site is not working on a slave account.
In order to change the password of your slave accounts, it needs to be done by our Customer service team via phone call as verification is needed for the security of the account.
They will not change the main TPG account password as we can advise them specifically of what account you want to have a new password.
You may send me a PM with your preferred time and best number to be contacted and will arrange it for you.
Further to my message earlier, I have now arranged to have the passwords on three slave email accounts changed. This was done by Basil (one of the moderators) arranging for a TPG Customer Service Representative to call me during an appointed time window who, after checking ids, changed the passwords on the system for me.
For now, it does not seem to be possible to change slave email account passwords by oneself online.
I hope that helps.