Pro site privileges expire but payment goes through

Hi,

I'm having some issues with the Pro Sites plugin. I've gone through a year cycle with some of my clients where at the end of their Pro Site membership the payment on file (via Paypal) is charged but the membership's privileges are revoked. If the payment goes through shouldn't the privileges be renewed automatically?

This is an embarrassing issue because I get notified of the payment going through but then the client receives the email that their membership expired.

Is this a bug? Did I not set it up correctly?