If this was a business account, sue away, if it's a residential account, then tough sh*t.
Seriously, why do people feel so entitled now-a-days? This isn't water, food or shelter. It's a service, with other services available if you 'don't like it'.
This is regardless of who has the legal right here. The company that provided the service, assessed the cost of re-doing their infrastructure to suit a special case.
If there were actual damages occurred other than interruption of service, then I'd understand. But to sue because of the termination of a contract is just too crazy for me.