I had a pretty good experience with Pytes support in November. I own eight 48100R-C Pytes batteries, which were purchased at different times and had three different firmware versions. To address this issue, I reached out to them via email, and they promptly provided me with latest firmware, a monitoring and updating software for Windows (which differed from the one available on their website), an instructions manual, and a WhatsApp number to directly contact an employee for live video chat assistance during the upgrade process.
During the firmware update, one of the batteries failed and became unresponsive, essentially bricking it. However, the support guy, guided me through the steps to recover and un-brick the battery. They implemented two fail-safe measures to recover the battery from firmware-related failures. The guy assured me not to worry and that they would honor the warranty in the unlikely situation that the battery will fail to revive.
I didn't need to test their warranty replacement process because the battery came back to life. What impressed me was that approximately a week later, the same support representative reached out to me via WhatsApp. He wanted to check if everything was working fine and if I had any further issues. I found this quite a nice gesture.