Motorola FC ID: K7GT9500 malfunctions

Good day.
Thanks for your review of Motorola FCC ID: K7GT9500. I have a problem, possibly caused by the fact that I use it very little.

  • the sound is not transmitted to the partner. we can’t hear each other.
  • the call signal is not transmitted.
  • sound from another brand (Weierwei, a Chinese) comes trough, but sending with Motorola does not come trough on the Weierwei.

Channel and the small code at the bottom of the display are the same.
Communication one way from Weierwei is on channel 2.

What can be tha cause?

Thanks in advance.