modifying services

I recently called customer support to modify my residential services. during the call the customer retention person was not able to asnwer my questions and made me feel like she was trying to sign me up for services she did not tell me about. At the end of the call I told her I wanted to cancel all of my services.

I would like to talk to someone about my experience but am unsure who/where to contact. Do you have a recommendation?

Thanks