2.4 and 5ghz lights alternating, wifi down. Need router password reset as well!

Hello, we have been having really spotty wifi service. We use chromecast audio's all over the shop but everything is constantly disconnecting, and the wifi lights are blinking. Not flashing like data transfers are happening, they alternate at a stead pace like they are looking for connections. I do not have the router login anymore, and it is not set to default.  Thanks!