Just to make sure: You bought 10 6"strips = 60" /36" = 1.67 yd
Assuming that he didn't do it on purpose, he was most likely emberrassed that he made a mistake and that a customer pointed it out (let alone a female)
It is too bad that he couldn't accept his error and fix it on the fly.
Is this person an employee or part of management?
LQSs are only as good as their service and the best slection of fabric will not draw repeat business when the employees are inept or unfriendly. One of our LQSs just went out of business because the owner was a raging [fill in the blank].
I would let the owner know what transpired. It is the owner's responsibility to train the personnel on the meaning of customer service. Arguing and belittling is NEVER good customer service.
If you don't feel comfortable talking to the owner, I'd suggest email.