There are always at least two different truths or realities in every company vs. customer conflict; what the customer believes and what the company believes.
For example, Fictitious Moulding Corporation has been in business for 88 years and they have always allowed customers to call in their orders instead of mail, fax, email or text them in. Last year, Fictitious got in trouble when they took an order for 1½" round over moulding and the customer wanted ½" moulding.  

Notes by customer service said 1½-inch

Fictitious checked its records, and the notes written by the customer service rep on the phone said 1½".  Fictitious had also emailed the order for acknowledgment to the customer showing the 1 ½” size.   The customer didn’t want the larger size and returned it.  That started a big, “He said, She Said” battle and eventually the customer paid a 25 percent restocking fee to put the moulding back on the shelf at Fictitious, but they never bought from Fictitious again.
 
To stop this from happening again, Fictitious implemented a new policy that all acknowledgments must be signed and returned before they will begin production. Problem solved.
 
Unfortunately, the other customers who were used to calling in orders now were burdened with extra paperwork of printing out all acknowledgments, signing them, and then scanning them to be sent back to Fictitious.
Over the next few months, Fictitious started to see their sales slowly drop as the competition ate away at their disgruntled customer base.
 
We all get caught up in the drama of blame and being “right” whenever the customer is complaining about our product, service or people. We focus on fighting with our own customers about who promised the delivery, why the color is wrong, etc. We spend huge amounts of time building policies and warranties to cover our ass “in case” an incident occurs again.
 
It’s like we are back in high school and the vice principal punishes everyone with detention because one stupid fool smoked in the locker room.
 
When we focus on who is right instead of what can we gain or lose, we end up losing business. You are a company, not a court.  So it really doesn’t matter who is right in a customer conflict. What matters is “do you want to keep the business or not”?

Don’t create policy that hampers business with all customers

If the customer has made a one-time mistake, let it go and carry on. Don’t create a policy that hampers your business with all your customers.
 
If the customer is constantly making the same errors in ordering, then focus on that one customer.  Take the time to train them on the right way to make their needs known. If they cannot learn to order correctly, then raise their price to deal with the hassle of handling them or fire them.  Sending that one problem customer to your competition will be the best decision you make this year.