EX2700 not connecting

Hi I had been using my extender fine for months then I changed the bandwidth on my router, have since changed it back but still can't connect.

I have done all the steps a ridiculous number of times on different devices (iPhone,iPad,windows laptop) including after a factory reset and plugging an Ethernet cable directly from router into the extender but still the same outcome:

power and wps lights solid green, device light green when trying to connect to the WiFi.

whenever I click on the extender name in WiFi it takes me to the net gear sign in page or new extender setup page following a reset. It never finds my router on the assistant (and doesn't connect via wps) so I have to input manually (as I did before the first time last year when it worked), put in all the correct info and it either kicks me off the page and back to WiFi menu or just takes me through the steps, I click continue and then I am back to square one with no connectivity.

any help much appreciated as its driving me up the wall!