Gigablast Problems

I recently upgraded to the "Gigablast" internet, in my area they said it would be 999[Download] / 35[upload]  it was great for about two days. Then my speeds got as low as 100 / 1 with the best test being 300 / 3 . So I called Cox and after resetting on my end and there end, we scheduled a tech to come. Tech came switched a wire outside, ran some test then asked to connect directly to the PC and we ran some speed test. Got around 600 / 30 after a few more speed test we got around 800 / 37. Everything looked and ran fine. No more then 2 hours later I am back to 100-300 for download and 1-3 upload. I stream on twitch.tv and my upload is very important to me and i should be getting around 35 and cant go passed 3. I need to resolve this problem as this a form of income and can no longer stream because of such a low upload. Any ideas at this point would be helpful because a new modem, new router and a tech coming changed nothing. im stuck at 137 download and 1.37 upload as of now.