Maybe the APN information is not right, you could confirm that with your ISP. You could attach some pictures, such as status page or something maybe help.

It seems that you have your Guest network with no password. It's open and anyone can connect to it. Maybe you could set password for it.

Hi, I got this beta firmware, you could have it a try. http://support.tp-link.com/f/36ca372485/?dl=1

Er, M7350 supports only 2.4G wifi.

I'm afraid this is impossible...

Yes, of course. But I wonder that which password you need to reset, wifi password or management password. Anyway, you can just login to the management page by entering tplinkrepeater.net in your...