Sorry, please clarify for me so I can understand better: are you saying that your call was limited to 7 minutes after you paid (added value) to your Skype account? It seems to me it would only be if you had insufficient funds (credits) available on your Skype account.
My husband uses Skype for calling land lines all around the world and his calls are certainly not limited to 7 minutes. In fact, he routinely has 2 hour long conference calls to a German office (we’re in the US)—and he never has to call back.
If you’re talking about the free trial—then perhaps Skype is telling you they will limit you to 7 minutes for the free trial call.
If you’re looking for a FREE way to communicate via Skype you can always “Skype” directly (video chat or just voice call) from one Skype user to another. Just requires you both to have a Skype username and be at the computer. That’s how I usually use Skype.. I video chat with my family whenever (and so far from wherever) I travel for work. It’s completely free of cost—just requires a bit of advance planning (usually an email to set a time for the kids to be ready in front of the computer) on when we’ll “Skype”.