Yes, if the player has been gone for a while, we need to make room for the newer players constantly coming in.
Seeing as how you registered your forums account on April 16th, I can only assume that you bought your 16k house roughly at the same time. So about two weeks later, if you haven't shown up even in a whole week, it would've been reset.
You can make more than 16k in 3 drug runs, I'm sure you'll be fine.
