Pressure selling agree with it or don’t?

Everytime I turn around, I have a marketer calling me. It’s not that I mind them calling me. It’s just frustrating because most of them are so rude! When I answer the phone it’s usually because I expect a customer to be calling. But when I pick up the phone and it’s a marketer, I do not get frustrated, unless I tell them I’m sorry I do not have time to talk right now, I’m servicing one of my customer’s and I will have to call you back later. And then they will say: What I have to tell you, will only take 16 seconds, which I know that’s not true, but I give them a few minutes anyway. And then when they get done with their sales pitch explaining in detail what they want to sell me. I say to them, I appreciate it. But honestly I don’t feel that that type of advertising is really going to help my business. Then they further want to make matters worse for themselves by disrespecting my time. And basically repeating themselves over and over, hoping that I will be sold on what they’re trying to sell me. Honestly when I have told them, I have to go and they do not listen to me, I have no other choice but to hang up the phone.