Pro Sites expiring accounts after payment received

This week, I have had 2 prosites expire after payment was received!
We are using a pay to blog with 30 day free trial.

In both cases, the subscriber paid for the annual account but the next day the system sent them an expiration notice and shut them down.

I believe in both cases, they had been having a difficult time logging in so I had manually extended their sites a couple of days until they could login.