absolutely not---i always return any and all materials left over- if the customer requests i trim the quilt after quilting the scraps- fabric & batting are folded & placed with the quilt- if the customer does not request i trim the quilt it is returned exactly as it comes off the frame. i have customers who do not want their excess batting- but they let me know that- i have one customer who never wants the scraps. they are still always with the quilt when she picks it up- it's her choice to give them to me-or take them with her...i would never (assume) to keep someone elses excess fabric.
you should either call or send an email asking for the rest of your fabric- maybe it was layed next to the quilt & just missed when she grabbed it to return it to you & is just laying there...could just be an honest mistake- with so much going on she may not even realize she has it- let her know- (i would want to be contacted- a couple weeks from now she may not remember where it came from)