I just received this from DCH:
It seems that Teamspeak have blacklisted us but we DO have a bought license from them.

We will be sorting this today. I will e-mail everyone the new IP which i have sorted with Team Speak, I am also trying to let this one work also.

I will keep you updated today. This issue will be solved today.
In regards to VoX saying that we do not need a licence for our server from DCH, we do. Even if we are not paying for the TS server, since DCH is a profit organisation a licence has to be paid for.

If we were to host a Teamspeak server on our own, say on our dedicated server, I do not believe that we would have to pay for a licence. This is because we are a non-profit/non-business organisation.