Charter Speed Issues (and really high ping)

I have 30 Mbps service from Charter, so I have come to rely on my Apple TV and Netflix. Recently, my speed drops from 6PM to 10 PM from 30 Mbps to less than 1Mbps. During that time, my ping goes from 50 ms to 1200 ms. This is pretty consistent. Meanwhile my 4 Mbps upload speed stays right around 4Mbps. I had the technician out and he told me that my node is overloaded and that it would need an upgrade. He also told me that they weren't planning any upgrades.

What I'm asking is, before I start making demands for refunds, etc, does this sound like a rational explanation of what is going on? I haven't been able to use my Apple TV (well, I have to plan ahead and download the movies etc in the morning, then stream them from iTunes on my PC). There is no other ISP in town, so I don't have much leverage. What can I do?