Can someone help me with my JioFiber

Installed a JioFiber 2 months back and since day 1 it has a network issue with my phone and tablet,whenever I'm in any other room other than in which it is installed,it will give me a 1-2 bar network or get disconnected,i thought maybe it was because of the 5g band,because my phones weren't connecting to the 2.4ghz band and hence the range was very less,so I saw some videos on how to seperate the two bands but I really couldn't do it Anyone else who faced or is facing the same issue? It would help alot!!