I get to play detective
We recently had a cable modem disappear from one of our units here at work. The renters who stayed in the house last claim they don't have it. I don't believe them, nor does some of the staff, just based on the fact that we had trouble with these folks.
So the modem is gone, and we ordered a new one from NewEgg (for $82 -- the cable company wanted to charge us $250). But there's only a couple thing you can do with a cable modem: pawn it off on someone, or hook it up on your cable system. Generally, to get it to work with a new cable system, you have to give them the MAC address. That's how many cable companies verify that you're a subscriber is by the MAC address of your modem -- if your modem's MAC is in their database, you can play.
So what am I going to do? Get the MAC address of the stolen modem from our cable company, and then call the renter's cable company, just to see if they have that MAC address on their network. I'll keep you posted with my results.