i think you really need to move away from the mom and pop type hosting companies so to speak at this stage of the game and jump on a strong backbone like at&t, verizon, or fujitsu who provides verizon there services.

Pick a company that monitors there systems by more then one person at a time if at all. Some of the hosts listed do not even look untill a problem comes up. Again you need this place watched over by a group of people 24/7.

I know the three i listed up there are not cheap see more by any means, but i think you are going to have to spend some coin on this to be sure this dont happen again. I think if you pick a big company that is the "backbone" of the internet a red flag will go off much sooner rather then later.

I also think if you pick a big company they will be more willing to track down and take action of any type to find the person/s that are up to no good.

Just my thoughts. this on is going to cost some money.....