Why don't the seed companies write clear guidance? It doesn't have to be wordy. Here's my suggestion if they're really pushed for space: "Store in an air-tight container in the fridge." If they can stretch to an extra THREE words, then they could be really clear. "Store in an air-tight container in the fridge, at a constant temperature."
Now, that's not hard, is it? After all, we've paid for this product, haven't we? Success is measured in germination rates as well as in the health, taste, and abundance of the plants we grow. So why don't the companies provide clear instructions on how to look after their products?
They also need to be stored in the dark, so the seed envelope, and ideally the storage container, needs to exclude light.
Kew, who run the Millenium Seed Bank Project, recommend glass jars over all other containers. Check out their advice for yourself.
Instead, buy a couple of glass jars with rubber-seal necks, or some decent lock-lid tupperware containers. Group your seeds however you choose - by season or by veg type, herb or flower - and store them in your fridge, at a constant temperature, excluding light.