Thanks Andrew.
You mention "once it has been validated within the first 24 hours", actually this was in less than 24 hours, so do you mean I shouldn't face this problem after 24 hours elapse after the unlocker installation?
The trial and the unlocker were both installed from Google play store using my Gmail account, not from Poweramp website, would this make a difference? I also installed the app and the unlocker on my phone using the same Gmail account from Google play store, but I'm not facing such issue on my phone, although it was in less than 24 hours.