I'd first unplug your cable box from the wall for 5 minutes and plug it back in. Sometimes this will reset a troublesome box. Also check that your cable connections are securely attached and there's no damaged wires.
I'd call tech support if that doesn't work and have them walk you through so you can at least eliminate some possibilities before you have them come out for a service call.
You need to tell Time Warner that they need an exchange by mail program like the one from Verizon FiOS so that they can exchange bad boxes for people who can't be home, and that CTDI can help them set it up.