Model : TD-W8961ND

Hardware Version :

Firmware Version :

ISP :

Hi , I have a strange problem that I couldn't find any solution for it,
I have 300Mbps Wireless N ADSL2+ Modem Router , model TD-W8961ND,
The wireless suddenly stopped, the router works fine only with LAN cable.
When I enter the administration page and then to the Interface setup section, I can't find under it the WIFI section, the only sections there are Internet and LAN.
I resat the Modem couple of times but it didn't work.

How can I solve this problem?

Thanks :)