Obnoxious sales people

Sales people talk to you like they know you for years, they do not listen when you tell them that you are happy with the current unit in your vehicle, so they are basically harassing you, and if one person "okay nê" or "oraait nê" after every sentence when you speak to them, I will definitely blow my top. Where did they learn to speak to customers. They as the company representative is the first contact a customer will have with the company, and the way you speak to a prospective client shows a lot about the training of the said company. I would seriously appreciate it if they remove me from their calling list, I am in general an very nice person, but please do not test the boundaries, yes, being in sales and getting a yes in about 2 out of 20 people you contact is draining and can make you negative. But PLEASE listen to what the person have to say, and in future not that many people will end a call abruptly while you are in mid-sentence....