Losing Defensive Weapons! (Fearless Blue)

Yeah i was wondering, Why am i losing my Defensive Weapons? I had like 1000 Defensive Missles now it disappeared when i log in. This happened more than once when i usually log in and pretend that nothing happened, So if anyone knows the reason then Reply.

You're probably burning through them, with a large # of Def. Missile batteries. Go to world trade / products in stock (buy/sell)
And, look for defensive missiles. You'll see two numbers: one is the number you burn / month, the other is your current stock. I'm guessing this is what happened; although, another scenario would be:

One of your units that has defensive missile batteries, got stocked (or a version of that, ie Remote Depot)

Why do we use them if not at war? I use up loads too...