I <p>I asked the CM and here is the answer:
https://www.tibia.com/forum/?action=thread&threadid=4754105&pagenumber=5answer.</p><blockquote><p>The game uses internal IDs to determine in which order it deducts money for rent. However, you won't lose any of the houses immediately as a grace period of one week would kick in for you to pay your rent.</p></blockquote><p><a rel="nofollow" href="https://www.tibia.com/forum/?action=thread&threadid=4754105&pagenumber=5">https://www.tibia.com/forum/?action=thread&threadid=4754105&pagenumber=5</a></p>