Have you used the insim to set auto bill pay to on? I've been using that and no one has been evicted. Also, is the mail box an apartment type? If it's a house looking mail box you've got a replacement mail box somewhere in your game. This thread covers that trouble
http://www.insimenator.org/showthread.php?t=91348Also, I have started using Monique's computer in some of my homes and apartments to see how it works with AL and it hasn't caused me any problems (yet) but I won't swear to it until it's updated.