Issues getting the full speed for the gigablast

I am having the same issue is whether having come into signing a two-year contract for their giga blast. It's actual speeds is running right now something between 70 Mbps to 110 Mbps, the highest of everything it has been about 170 Mbps. I think they got me on a bait and switch because I was paying $91.83 for their preferred 150 if I would lock into a two-year contract at the same price. What they didn't tell me was that the preferred 150 had been reduced to $53.99. At the time they supposedly installed a giga blast I inquired as to whether or not they didn't need to change the modem. Was assured that the one I had was what was required and all they had to do was throw a switch or something and am good to go. In cruising through their blog now I see they say that a panoramic Wi-Fi gateway for an additional $12 per month or something like that is the recommended equipment. We used to have spectrum and occasionally would have some issues but nothing even close to this.