I can't get hold of my sales rep for support, who should I contact?

Hello, I have several issues that I need help with but my sales rep is no longer answering my calls/texts/emails.

I was unknowingly charged for the phone device, my sales rep said he'll try to get credit to my account, but I haven't heard back. I also need assistance with setting up another phone but cannot get help. Who is the best department to escalate this to?