Mailchimp alert messages

How do i change the alert message text from “Member exists” to “You are already subscribed to our newsletter”.

Also the position of the above alert message and success alert message are appearing above the form, pushing the form down and the alignment of the entire block goes for a toss. How to change that? I want the alert messages in plain text appearing below the mailchimp form in a way that it doesn’t disturb the alignment of the block.

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