Payment limit exceeded

i see that there are limitations to my plan regarding paid submissions.  However, I have an "unpaid" form that we are not recieving payments on and that form keeps becoming disabled.  Can you explain to me what is going on?

I see all your other forms have been disabled in your account. That is the reason they are not available, please follow this guide in order to enable it again: How-to-Enable-Disable-a-Form