Audio Technica Mic Receiver not working

I have an old Audio Technica Digital Reference ATW-R700 mic/receiver. It was working perfectly until a month ago. Now it no longer detects my mic and when I press the Select button, it doesn’t change the input channel and looks like it is stuck at channel 0 (0 channel is reserved and not available for use). I have attached the video here and also the YouTube link that shows how it is supposed to work. Any clue??

Video that shows how it is supposed to work:
Link1

Video that shows what is going on:
Link2

Please help.

any update?