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.
V
Communication one way from Weierwei is on channel 2.

What can be tha cause?

Thanks in advance.

Frank1