I know on RedGuides, when you had a free month added, you had to unsubscribe so you didn't get charged. That's because PayPal takes care of the subscriptions, not the website, and PayPal has no idea how to know that you've been awarded a month here. So, basically, just cancel the PayPal subscription, then resubscribe if needed after your free month is up. I'm pretty sure the Subscription Manager here, just adds on a month if you pay, so you should be good for 2 months now.