I have some doubts about the skill level of the representative with whom you spoke. In recent years, the technology is improving constantly. Personally, I refused to have such performance. At this time, I subscribed to 5mg service because I was told it was the best they could offer me. Some technicians came by and corrected some of my problems I had. Among these, one of them converts me to pairs-bounding. Basically this means that two links comes in the modem. What follows may seem unrealistic but I assure you that I am now at 30mg. Besides I also have three Fibe receivers who must consume about 6mg each of bandwidth.
I am confident that it is possible to improve internet speed. However, if you are satisfied with the satellite TV service, my recommendation would be to keep it intact. Having had both, I think you have nothing to gain and much to lose to migrate TV services to Fibe. With a rough idea of your television habits, I could clarify my statements.