I had the same deal. When spectrum took over my only option was to go from $15 to $70 if I wanted more speed. In addition I felt that they made the 3 mbps worse over time with more and more interruptions and reduced speed.

As far as spectrum goes they are pushing for higher speeds for a very high price. It feels like only being able to buy a Porsche as a car. Certainly a nice car but very expensive for most of us.