You can buy containers for 120 film. Some films even come with this from the factory, mostly Rollei and Maco I think. However, I would not put 120 film back in the freezer after exposure. I had once stored an exposed 120 film in the fridge and forgot it there for almost 4 years. It showed some strange bands near the edges after development that protruded into the negatives. This is not to say that re-freezing after exposure might definitely hurt, but I would make a test before re-freezing really important stuff.