For Windows Phone developers who got email notifications regarding your AppHub account renewal need not worry about the issue. It was an issue from Microsoft side and they are working on it. You can continue to use your AppHub account for publishing apps, etc,.
From AppHub forums,
Account Renewals Issues Will Not Impact Your Account
Many of you may have received one or more email notifications that your account is going to expire or has been cancelled. Unfortunately the instructions in these emails are not correct and therefore you are unable to process the renewal. We are working through the issues and as soon as we have the renewal path up and running there are no actions for you to take at this time. Please note that your account access, usability and apps published will not be impacted in any way for any account type while we work through this issue. As soon as we have the actions to be taken in place, we will provide instructions on how to do so.
We apologize for the confusion and concern this issue has caused. However, it is very important to note that you will not be negatively impacted by this backend issue in the interim. You will have full access and use of your App Hub account and your published apps will remain published.