[Dagothur]

Well, it's possible the connection issue is within your server... but I'd wager if you haven't done or installed anything funky that the issue is your game traffic being dropped before it reaches your server. If the issue is with your host it doesn't sound like they will look into it unless you can provide some proof.

Any details on how the filtering is configured? Do you have both filtered addresses and unfiltered addresses?

Do you happen to have another service with the same host, preferably in the same subnet?