I used Peak10 for a few years, but as my business grew I out grew their facility and abilities. I am not surpried to hear they don't respond to calls.
They talk a good game about redundancy and tech support. But more often than not I was retaining outside help at $100+ an hour to find their network problems and explain to their techs how to correct it.
It was not unusual to see network outages for 6 or 8 hours becuase something went wrong with an upgrade or during maintenance window. One time it lasted an entire day.
They are great to work with, friendly and helpful. But even paying the bill was difficult. Sometimes calls were not returned for days if at all.
Unfortunately the network support was the same. At one point, they told me they could not find the problem and it might be gremlins.
Am I supposed to tell thousands of hosting clients I don't know why their site is down but it might come back online for any reason at any time?
The have a great business model, smart business people, and dynamite sales people but lack support and technical ability to operate complex networks.
It may be getting better, but I bailed as soon as the opportunity presented itself.
There is nothing worse than spending hours looking for problems only to find it is not your problem at all but the datacenters router configuration.