I’m not familiar with that model, but from what I can tell the T80 seems to be a PMR446 walkie talkie similar to the Motorola Talkabout T400 FRS/GMRS Radio we carry here in the US.
Even if the battery shows a full charge, if it is weak or damaged it may not be able to handle the power draw to transmit when you press the PTT. Try swapping the battery with one from another radio. If it resolves the issue, your battery may need to be replaced. If not try the next step.
Clear out all CTCSS and DCS codes, Group Mode, direct call, and call tones on the radios. If the radio transmits, it was a programming issue. If not, you may need to contact the Motorola support line in your country.