Surfboard SB6141 Ports Closed?

[SporkyMcForkinspoon]

I recently got annoyed at TWC charging $6/month to rent me the modem that was free for a number of years, so I bought my own. Ever since I have had problems with my port forwarding.
At first I thought that it was a problem with my router, and tried a number of things including putting my computer in a DMZ and nothing helped. Finally I tried connecting my PC directly to the modem. It turns out the ports are all still closed.

After doing some googling and not finding any solutions quickly, I called TWC's tech support and they told me that:
A)They thought my modem was defective.
B)That any settings that needed to be changed I would have to do myself, and if I wanted there help I should have just kept renting.
C)To call Motorola.
and D)That in the event of a necessary firmware update, they would not push it even though DOCSYS is supposed to be impossible for me to make any changes or upgrades myself.

I'm reasonably certain that this is being done intentionally to punish people for having the nerve to not want to pay them extra for no value added, that said, is it possible for me to hack the modem to open the ports? Might I have a defective unit? Has anyone else had this sort of problem?

 

[popatim]

You access the sb6141 configuration screens at 192.168.100.1
If TWC has locked you out then they are responsible for making changes.

 

[SporkyMcForkinspoon]

You access the sb6141 configuration screens at 192.168.100.1
If TWC has locked you out then they are responsible for making changes.

Although I can access the configuration screens, the only user changeable settings are to reset the modem or return to factory defaults, I have tried both with no success.