how to remove skin ad buy license now

I am using this plugin grand fia gallery. i have downloaded some skins from here:

https://photogallerycreator.com/grand-flagallery/

but every skin has a label ad (buy license now). how to remove this ad. as plugin has only xml file that do not have any option to remove what i found is i need to buy a license for $24 .
but i want to remove this ad is there any option to do this without purchasing this license. the plugin gives only one skin for free.

if we can download other skins then why it said to purchase license… ??

Plz help if someone have the solution..

https://www.ads-software.com/plugins/flash-album-gallery/