Form reports transaction denied but actually charges Credit Card

This is a pretty serious issue. Just installed this on my client’s site. The form reports the transaction was denied, but when checking my credit card I have been charged the amount I was trying to pledge.

(I have a hunch it is not clearing errors… I tried submitting the lowest amount possible in the custom amount field. First $1, then $5; both times I received an error saying I need to donate over $5. I think those errors aren’t clearing on submit and then it erroneously is reporting a denial on post)

Site is here: https://www.weema.org/donate/

Additionally, is there any way to test this plugin without submitting real funds? Would be helpful if there was.

Thanks for looking into this and hopefully fixing it.

http://wordpress.org/extend/plugins/piryx-in-wordpress/