Being from WI and a longarmer... alls I can say is, I'm sorry. I can't say this hasn't happened to me, once is enough though. When anything goes wrong on a customer's quilt I always take the high road.. meaning I call, write or whatever, tell them of the problem, and fix it for them, and give them something off of the quilting (free batting)
It is hard to admit our faults sometimes.. the pressure of this time of year is hard to take for anyone who gives a service, but it is not an excuse to make a mistake with out fixing it the best you can.
One thing you can try is Heat and Bond, removing it from the paper, and stick the gluey stuff (quilting term~I think)
under the tear, next to the batting. Put a teflon sheet on the top and press. I have another product I have use on clothing, Bond, it is a powder that is like the gluey stuff.
It patches pants, wool, anything, even hunting clothes.
Hang in there!