You give him a quote of a high amount and a really far out time frame. Sure I will do it, it will be 5x amount and my first open slot is about 12 months from now, and 11 months from now I will need 100% of the payment up front, so you want me to book you for it?
No? ok have a good day.
Can she sue you? Sure, you can sue anyone for any reason. The problem will be, she will have to go you to where you live to show up in court unless your local small claims judge does online cases. Basically, everything will have to be in your legal jurisdiction.
Most likely what they are going to do is file a charge back, you can respond back to credit card company that you are working with UPS and investigating to see what happened with the package. You can also let them know that at this time it appears as if the package did arrive, but you want to make sure it wasn’t left in some spot that they didn’t look or something. The credit card company will most likely side with the customer though and refund them.