I would guess you have gone over your limit of 300 items by quite a large amount. Every time you relist an auction item, it is taken off your total of 300 per month and you have more than 500 completed items for March already.
You can find how many free listings you have used on your selling page.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)