Where to file complaints regarding misinformation from Satisfaction Department agents?

As a long time customer I'm beginning to lose faith in Videotron every year especially with their customer service practices.

After a very frustrating day of having a quote generated by one satisfaction agent and then only to be told by subsequent agents that they will not honor it, where can I file a complaint regarding these agents for misinformation?

Additionally how could I escalate the situation? I was told by one of the last agents that a supervisor would contact however I'm not confident that they actually will...