I find the response you got from the manufacturer troubling. A room in 60s is hardly "cold." It seems more likely that this product isn't performing as intended. If you did put it down twice in efforts to fix it, you may have worn out or loosened up the locking seams. Try reinstalling it one more time, but this time instead of simply locking it, put some glue into the seams. When laminate is being installed in damp areas, glue is often recommended. Use a yellow carpenters glue, insert it into the locking groove, lock the flooring together and let it dry. You want to apply enough glue that a little bit squeezes out when you lock the plank. Wipe it away with damp cloth when it's still wet. If you have trouble getting the boards together - if there's a gap between them - use a strap clamp. Strap clamps are similar to what you see on backpacks, with a racheting mechanism. Put it around the flooring and pull those pieces together as needed.