@Ahmand 

Thanks for the update.

Have you tried to change the 2.4ghz channel and channel width, such as channel 11 and 20mhz?

And there is a beta firmware for TD-W9960 that improved the stability, please refer to the private message to update the beta firmware first:

If It did not help, could you please send an email to support.forum@tp-link.com (please add forum ID 556496) with the following information:

1. Some screenshots of the web UI>Advanced>status page(internet + DSL status section) before and after the disconnection.

--Since it is mentioned that the mobile devices are already disconnected and would not reconnect to the router until a reboot, would there be any chance that you could find an Ethernet device to get these pictures.

2. The system log after the internet got disconnected.

Thank you very much.

Best regards.