eWelink zigbe in the application

I have a permanent problem with the fact that we have properly paired, stored and updated zigbe type device, regularly once a week it disappears from the app in the phone but also from the web interface. Simply, the application arbitrarily deletes it. I am a paying customer with an annual subscription and this kind of behavior makes me angry . When zigbe disappears from the app and we re-pair it again, it disappears again within a week , But the control LED on the device lights up as if it is properly logged in and paired, so both the red and green LEDs are lit thanks