I'm very sorry for any inconvenience. We definitely want our customers to try and test our software before buying. This makes for very happy customers and is good for business. Since we offer the 15 day trial, we have very few complaints and very few returns. It also makes our tech support much easier because we're dealing with customers who actually like the product (think about it). We would never offer a fake trial (that would really piss people off).
So just to clarify, the 15 day trial is very important to us, our business model, and our potential customers.
With that being said, the trial version must have expired early for some reason. When the AudioLabel trial version is installed, the install date/time are saved on your computer. Every time AudioLabel is started, this date/time is checked to see if 15 days have past. There is also a check to see if the computer clock has been moved backward from the last known time. So, it's possible to expire the trial version early if the computer clock is changed after AudioLabel has been installed (not to say this is what happened in your case - just explaining).
It's also possible that AudioLabel was installed on your computer previously. Even if an older version of AudioLabel was installed on your computer years and years ago, the trial would be expired today. The AudioLabel trial time does not reset when a new version of AudioLabel comes out.
Currently, the only way to get another 15 day trial is to install AudioLabel on a different computer. Hopefully you have another computer or laptop you can install the trial version on and test (and get the full 15 days).
Please let me know if you need further assistance.