I use this module to drive a bipolar stepping motor, but I want to increase the voltage because the torque is insufficient.Will it work without problems at 12V or lower?

I have not yet contacted customer service.
Is exchange correspondence possible?

I have purchased the M5Stack Stepper module twice so far.

The first is April 30 of this year and the second is June 18 of this year.
This module is said to support 9-24V input, but when it was used for the first time, it actually didn't work when about 22V was input.
After that, it was operated by dropping the voltage to 16V.
What arrived at the time of the second purchase did not work at 16V, and at the moment when the power supply was connected, the M5StackCore stacked on top was destroyed.
I was able to operate by dropping the power supply to 8V. Why is it so unstable?

I have bought 6 M5StackCores and 5 Stepper modules so far. I want to get a stable one.
Is there no way to operate stably above 16V?