So, not a phone call but an email asking for a refund on their tickets for two performances. I looked through their account and noticed that one of the dates they provided was incorrect and politely emailed them back to provide info on the refunded ticket, as well as ask for the order number for the incorrectly dated performance.
I even wrote in detail how to find it. Snd I just noticed that they gave me the lowest rating available on the survey and left a note saying
“the information on the date of the play is incorrect; it was not March 5th but March 25th, as stated in my email. I will look through my emsil from SO LONG AGO to provide the receipt”
And then they emailed back with “I said it’s March 25th and now I have proof. Change it and give me my money.”
And on the bottom, they attached a PDF that is a fill-in-the-blank invoice from Microsoft Office 2010. Luckily, one of my coworkers intercepted the email as it came in and looked at their account and confirmed it on an internal note for the email chain that we indeed habe it listed on March 5th and not March 25th like these people claimed.