When a shop orders fabric, it is usually 4 to 6 months before the fabric will arrive at the shop.
If it's a Moda line, they will only print what they have pre-orders for. Then once it's gone, it's gone. There are very few exceptions when it comes to re-printing a Moda line.
At the shop where I work, we will write the customer's name in the order book, then call her when the fabric comes in. But I don't know how other shops (or online shops) handle pre-orders.