Rude Call Centre Agent

I just got a call from Cell C offering me more data and a router for a few hundred rand a month. I explained that I had enough data and would not need their offer, the agent put the phone down in my ear. There not many things that get my back up to this degree, but not having the decency to say goodbye is one of them. You are a call center trying to generate revenue and that is how you behave? What makes you think that this attitude is going to make me even remotely consider the next offer hat comes along from Cell C? Disgusting behavior!