Not getting the 50 mbps I'm paying for. Please help.

After moving a few months back I starting having issues with my streaming speeds which I thought was weird since I literally moved less than a mile away. After trying everything I could i decided to upgrade the speed to the 50mbps package. I have a Netgear N300 WiFi Cable Modem Router Model:C3000 DOCSIS 3.0. Since upgrading the service I noticed some improvement at the beginning but within a few weeks the service was back to terrible. The 4 speed tests I've run today have been: 0.75mbps 12.2mbps 8.99mbps 7.55mbps. My jaw dropped when I saw the 0.75mbps. I'd never seen it test that low before. I am paying for 50MBPS!! Please help.