One of our user's mail outgoing account is disabled.

Actually, the account was probably hacked, as there was many spams in "sent messages" (of course we didn't sent spams). We changed password and activated 2 steps auth to secure the account, now we want it unblocked.  When I try and enable it (once secured), I get the error message:  Operation permitted for paid user(s) only.

We also tried to unblock via the link provided in the message indicating it was blocked, but unsuccessfull.  I tried to send an e-mail to support@zohomail.com 2 days ago, but still no answer. So trying to post in forum, we really need to unblock it quite fast!

Thank you