Wirless router keeps disconnecting C3000 – N300 WiFi Cable Modem Router

Hello, C3000 – N300 WiFi Cable Modem Router, and after about 2 years of working perfectly all of a sudden it's not working anymore. It keeps disconnecitng about every 5 minutes. I have restarted it, re-booted the router, ping tested it, and then I even called my provider spectrum and they came out tested it and ran a new cable and still it keeps disconnecitng. They said it was my router, but when I changed to an old modem an old cisco modem that modem worked but the connection was low and bad. I called spectrum back and they are sending someone out in 2 days because they said the connection is low, but I wanted to know if there is anything I can do or ask them?  I check my connection Netgear genie and it says it is good? Just the wifi connection keeps getting disconnected.  Is it possible firmware?

This has never happend to me before so I wanted to avoid purchasing another wireless router as I don't have the money to do so right now. thanks.