Hello guys!

I was wondering how can i change the way the script works right now with the number of listings, as example: When someone purchase a plan (live for 365 days), he is receiving 50 listings. If he uses 2 and after a while he sell those 2 listings, even if he deletes those 2 he doesn't receive them back, so now he has only 48.
I would like to give them a number of listings(50), and they be able to add and delete listings and still have 50 listings (if they delete all)

Could someone help me with an advice or maybe the file that i need to modify ?
Thank You !!