You’re at the wireless store. Customer service is just trying to be helpful. They ask you for your IU account information to help you set up your new phone.
Don’t disclose these details. If you did, simply change your passphrase.
Learn how here:
Writing down your passphrase can leave you just as vulnerable. Don’t share your passphrase with anyone — even with friends, family, or computer support personnel.
For more, see: