Extruder increase temperature
Your printer does seem to have a firmware problem and lack important safety features - it should have stopped the moment it went 300°C measurement, beeped like hell, and shut down with an error message about Thermal Runaway Protection. Immediately stop using the printer!
Before you try to print again, you need to make a proper firmware for your printer, one that has both Mintemp, Maxtemp as well as Thermal Runaway Protection actiive and flash that. While setting up your firmware, make sure you use the right temperature table for your thermosensor. How to do that is detailed here.