AC1750 WIFI

I have a Wifi Extender that I have had for a couple of months now and was working great. However we recently just upgraded our internet package which required getting a brand new modem to be able to handle the internet speeds. After changing this modem I have had problem with the nighthawk mesh extender. It will turn on connects to the modem the light indicating that the modem is connected is on but the light that is to the right of that which I assume meaning the extender is extending signal is not on and I have factory reset this thing 6 times now trying to get the installation set up but the app won't reset. is there a way I can delete this extender from the nighthawk app so that I can restart over? I can't figure out how at all and I can't afford Netgear's  high support packages so any help would be greatly appreciated.