Slow & Laggy on Ultimate service at 89130

For about three weeks I've been experiencing a bad connection. Originally it was slow with lots of lag in games and buffering when I watched streaming. I contacted Cox via phone support and after a few reboots of my modem the tech said that they could no longer see it on the network. I've since then replaced the modem and still experiencing the problem with a new modem (Motorola SB6183). Tech one that was sent out was unable to fix issue, even trying a modem from the truck and it not working correctly. He left for the next job and when he returned it seemed to work directly connected to my PC. After he left I setup my network connecting it to my router (Asus RT-N66U). I didn't notice any speed slowdowns for a few days. On the second service call the second tech diagnosed it as my router since directly connected its fine, but on my network its not working. I replaced the router with a Asus RT-AC88U. Now about three weeks later, It's still just as bad as it was when I first called. I've also change out Ethernet cable from router to modem and still no change. 

This image is a wired speed test from my computer with my current setup (SB6183 modem, RT-AC88U router)

http://imgur.com/003QZte

Ping from router to google

http://imgur.com/mBNYMPo

Downstream channels from modem

http://imgur.com/BQHzD3C

Upstream channels from modem

http://imgur.com/ZmKn30z