If you fail to deploy your armies within the 1 hour time limit of your turn, you loose them forever. However, a deadbeat can skip 2 turns out of 3, and, provided he doesn't get eliminated in the mean time, eventually gets back all his armies.
The failure to deploy within the hour is often caused by a users computer crash or a problem with the users internet connection. It would seem more equitable to allow the player to deploy the armies that were not deployed within the allotted hour at the end of his next turn, just like we allow the deadbeats to do.