What was compromised? Specifically, what got hacked? If it was your own VoIP hardware or software, it's unreasonable to blame VoIP.ms.
If your VoIP.ms web portal got hacked into, and your password was easily guessed, or if you used the same password on other sites, one of which may have been compromised, that is also your problem.
OTOH, if you had a properly protected, strong and unique password, or otherwise have reason to believe that VoIP.ms systems were compromised in general, e.g. a hacker obtained access to their entire database, then you have a valid case. Please provide more details.