I had the exact opposite experience. After already owning a DM42, DM41X, and a DM16L, and I bought a DM12L for a client. The screen had several LCD segments that faintly showed as always on. I wrote an email and was contacted by Michael (the founder) almost immediately. He said they'd happily take it back and send me a new one, but it would take a few weeks for shipping from Europe. Instead he suggested that I first try putting it in the oven at 70C (160F for us 'Mericans) for a few hours. So I disassembled it and put just the PCB/display unit in the oven. And sure enough: problem solved!

tl;dr: I thought their service was great.

Although I do love my real HP's, too. I own maybe a dozen. I think the 32sII is my favorite, but I dearly miss my 41CV from back in the day. Maybe I should find a used one of those.

On the programming side: I definitely agree with those saying calculators were/are an entry to programming. My first programs were on an HP-29c. I thought I had invented binary search!

Can I ask when you had this exchange, which email you contacted (I've tried emailing both the support address and the individual addresses) and which email provider you use?

This was in early March 2020 (so, just pre-Covid). I was using [email protected], because I was responding to the invoice they sent me. And I self-host my email server. Hope that helps.