Just wanted to follow up. The Charter guys on twitter got in touch with me right away last Monday, and proceeded to solve my issues. They utilized the services of one of their network engineers to double-check the configurations on everything from my modem all the way up the chain to the local office. Somewhere along the way, everything suddenly started working as expected.
I also got another list of blocked ports:
- 445
- 593
- 139
- 1433
- 80
- 21
- 25
- 1080
- 8080
- 143
Now, to cancel my DSL lines 
