Sorry to read about the inconvenience. Here’s the engineer’s suggested steps to help rule out the cause root.
Measure the resistance of the hotbed thermistor to see if it is normal and feedback resistance value after measurement for judgment (must be measured at normal room temperature, preferably with feedback pictures).
Measuring method： The multimeter gear rotates to 200KΩ gear, and the multimeter measuring pen is placed on the terminal of the thermistor wire. Same method applicable to measuring the nozzle thermistor.