That is BAD SERVICE, no matter how you look at it. The others here are correct, it is stealing to charge you for extra fabric. It might be different if he charged you full price for all the fabric but ONLY if he told you first. I don't think I would have completed the purchase (of course when it's happening you don't always think about that).
You should difinitely talk to the owner, if that's the way they are doing business I would not do business with them.
Interested in how this works out for you.
Jo