I have had the exact same issue and finally today got them to drop me down to 6MB. Unfortunately it won't be done till Monday and I will be out of town all week next week so I won't know if it is better until Friday.
Just make sure to check you bill next month. We asked for a change in service on the phone end due to some quality issues and found a somewhat cryptic additional charge on the bill. Only after calling customer service to contest the added charge did we find out that they charged the additional amount because we asked for a change in service (which we were told was to be gratis).