Very slow Gigablast Speeds

Everything was working well for the past several weeks after signing on with Cox Gigablast. However, my speed is extremely slow at 0.35 mbps download and non-existent upload. We've called Cox a few times, and was walked through all of the steps. Nothing has worked. They are now telling us that the modem is bad. We just got this modem three weeks ago from Cox! According to the outage locators on the internet, there is an outage across my area, but Cox says that there is no outage. I really dont think we need another modem. Is there an update or something that needs to be pushed through?