Can't reach an address

I am trying to connect to my company's VPN and I am not able to ping it from any Comcast Business connection.  I have tried three different ones in the Chicagoland area.  This can be reached via a ATT DSL line and an RCN cable line.  I would prefer not to post the IP address in an open forum.  Who can I contact from Comcast to get support on an issue like this.