They, apparently, own their own datacenters and tout HIPAA compliant hosting. If they can't deal with incoming DoS traffic at the edge of their network I would

They, apparently, own their own datacenters and tout HIPAA compliant hosting. If they can't deal with incoming DoS traffic at the edge of their network I would be concerned... People who run botnet slaves large enough to get DDoSed by their fellow botnet masters are smart enough to own Voip numbers for verification. The verification keeps 12year olds off not really anyone else. But it also stops legitimate users from signing up.