Phones are going down faster and longer. iTel see...

Phones are going down faster and longer. iTel seems unable to find the problem other than blaming our IT company. The DDos is external and as a provider I would think there should be firewalls in place and the ability to find the problem has been left to us. I am so discouraged we have our life savings on the line and iTel does not seem to care. I have called the person involved only to receive a voicemail.