Internet speed is awful. I pay for so much more than I get!

Spoke to a rep on Tuesday and got no real help but rebooting my modem to factory reset. Cant send a tech. Look at this internet speed. I pay for 600 Mbps. I get a measly 68 to 71 Mbps internet speed!

I need some real answers. What's going on? I am not getting what I am paying for!