Hello AB1-AB1,
On your website I noticed this <input type="checkbox" name="mc4wp-subscribe[]" value="Yes">.
May I suggest you try with something like below:
<label><input type="checkbox" name="mc4wp-subscribe" value="0" /> Are you a Realtor?</label>
The name "mc4wp-subscribe" is required for the form to properly submit to MailChimp.