Why bluetooth earbuds signal is not stable?

1.Restart the bluetooth earbuds.
2. Please kindly check the compatibility of the mobile phone and calling 
communication quality.
3. Then confirm if the distance between earbuds and phone is too far or  
there are interference surrounded.If too far or there are interference, the signal 
will be not stable.
4.Please don’t stay in the signal reflective environment.
5.If tried all these still with problem,please change a phone to try.