[nickmyersdt]

I take the attitude of "my only purpose is to help this person".

I don't care what they say, how they say it's how wrong (or right) they are or who (if anyone) made a mistake.

I only care about "what is the most helpful thing I can do for this person".

I have apologised, explained internal constraints, identified where our processes have failed, offered video calls, empathised if I felt it would help, however I am mainly looking to "solve the problem this person has" within the limits of my authority.

Look for the facts, ignore the rest, and be helpful and kind.

Also, being sole developer and supporting customers is very hard. I'd be trying to separate me from the software and the customer issues, see them as independent from one another but nevertheless influencing each other (customer issues help you identify what to improve!)