Hello, Ahmedsa. At this point, were you able to reconfigure the wireless settings of your Linksys router as suggested before by pepper_mint? By the way, you mentioned that you have a gateway router. If you don't mind, kindly provide the following info so I would be able to provide you additional workarounds:
a. Model number of the Linksys router
b. Make and model of the gateway router
c. Name of your Internet provider
d. Current wireless settings (network mode and wireless channel) of the Linksys router
It would surely be nice to hear from you again so we can both fix this. :)