Received a phone call from Appliance Repair Experts offering apologies and wanting to turn my experience around. Asked what they could do to make the situation right. I explained that I was not looking for handouts and was just generally upset with the situation. They offered to resolve the discrepancy in the invoice and only charge me the service fee for the visit. Stated that the credit could take some time to post, so I'll keep an eye out and edit if necessary.
I think the resolution was more than fair, and this is the type of service (and response time) that truly make a company standout. A sincere "thank you" for doing the right thing. It's truly appreciated. I will be sure to refer anyone looking for repairs to this company.