I had a troubles with powering my SIM800L module. When it was powered from Arduino board using LM2596 DC/DC step-down transformer (which is used to lessen voltage to 4.1V) the module restarted every 10 seconds of its work so I have decided to power it up from 9V battery using same transformer.

After setting all up, I have pluged the wires, module worked for around 15 seconds and then powered down (signal LED was not blinking). I have measured the voltage and it was around 7.2V... I don't know how that can happen. I then set up transformer to 4.1V again but module have not started. Also I tried to power it up with 3.3V and 4.5V but nothing changed. Is there any solution for given problem? Have I burned my module?