Baggage service agent here to answer your questions.

Bags that are unclaimed are to be sent to IAH after 5 days. Doesn't always happen that soon unless the bag arrived without a name tag or any baggage tags. If your bag does make it back to IAH, we have a department that sends their time attempting to get the bag to it's owner via the claim form that was taken.

I can only assume that the phones were not being answered was because the agents might be busy with the flights and delays happening due to the extra security measures and the snow issues.

Hope your receive your bag shortly.