Cox is not passing on packets to the next hop when sending to my exchange server located outside the U.S.

Hi, Does anyone know how to escalate it? The tech support I talk to don't seem to understand. My exchange server is outside the U.S. and they claim it is not their responsibility to send it there. I have told them I understand that as there are intermediate global ISPs that will forward it but their responsibility is to pass it on to the next hop whereas they are dropping it within their servers. I shared the tracert that clearly shows that the last IP it communicates to is a Cox IP and it does not go beyond that. It seems to work at times though. I am forced to use my work VPN to send out emails. When I take my laptop to other places (where Cox is not the provider), it works just fine. 

I would like to give it one shot by escalating it before I will be forced to switch to another provider as it is affecting my ability to work. Does anyone know how I can escalate this? Thanks!