Hi, since you’re logged in to post this request, I guess the account is working. So use the “support menu” to open a ticket for premium support.
In your account page (see the top menu “account”), you have a license code to be copied in the Newsletter main settings. Then the extensions panel in the Newsletter menu is enable for the extensions installation.
I suspect you did not received the activation email. We received a purchase with a wrong email address and it is very similar to your actuall address.