Subscribe by Email doesn't check if email already exsist

Hi,

The Subscribe by Email plugin doesn't check if the user has already been subscribed. I talked with Michael in the live chat, which could confirm this, and he told me that I should write you here at the forum.

You can check the issue on the provided website by the provided URL in the bottom of the website.

This is a bit urgent!

Sincerely,
Mika