Well, typically I'd let my clients know to expect an invitation from me or a link to register *as a guest* (the link I sent out yesterday added them as members, not guests). Showing them a Gmail address that *I don't typically use with them* (in the email and sign-up page) appears more fraudulent than communicating like I should in the first place.

If I'd known my login email address would show everywhere I'd have used a different one.

Hi! We advise that you cannot modify the first administrator's email, but you can have several administrators, invite a member with the corporate email and then appoint him/her as administrator, otherwise, we can send him/her new coupons and cancel the old ones, as you prefer.

Best regards ;)