Thank You Box

Hello
I installed Boxzilla on my site. I use it to get people to sign up to my newsletter. I incorporated the short code for the Mail Chimp plugin and it looks and works fine except when the “Thank you…” box appears after the user completed the subscription process, the Thank You box contains the original box information in addition to the Thank You information. I do not want the original information displayed as the user already subscribed. How do I do this?

Here is the URL to the screen shot … http://optimisticbrain.com/bad-thank-you/

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