AC1900 model C7000v2 slow speeds

[Qwertyuiop0616]

Just got the modem-router combo yesterday and the Optimum WiFi man came in and set it up. I ran a speed test and it was very slow.
My plan is Optimum 300 and my speeds right now are 20-40mbps (download) and 14-20mbps (upload)
Should I get a new router?

[plemans]

How are you testing speeds ?
What wired speed do you get? 

Speed over 2.4gh?

Speed over 5ghz?

What device are you testing on ?
What site/app are you using?