@mohd_aadil. 

Hello, can we try to confirm some details about the disconnect issue you encountered with the WR720N, then we can try to fix it?
1. What is the exact issue, is the wireless unstable or both the wireless and wired connections are having issues?
2. Are all wireless devices or both wired and wireless devices experiencing the same dropout or just some special or old clients? When they got disconnected, is the wireless network of the WR720N still broadcasting or the wireless network is no longer available on all other devices as well?
3. How often does this disconnect issue happen? How did you recover the connection? It is suggested to reset it to the factory defaults and reconfigure it from scratch, leave all the settings by default and confirm again.
4. Is there any special activity that may cause the disconnect/drop out, such as high loading or downloading? How many devices are connected to the router at the same time? Try to disconnect some of them to verify if the connectivity is stable.
5. It is suggested to try with different channels, and try to find one with less interference with others. Change the channel width to 20MHz, then reboot the router and confirm.