i'm almost 99% sure you weren't provided a D2 modem if you just bought a modem let alone the last 6+ months.
Why D2 modems are not supported on Standard Cable anymore? They can easily handle that speed. I just bought Standard Cable service from Start this month, and now I have to already buy a new modem to get the new speeds???? This is not fair! What's the technical explanation to that decision to left behind all D2 owners?