Avoiding the aggressive sales execs is an uphill task

I try my best to avoid these guys carrying a bag, handful of papers and waiting outside office, bank, ATM and where not for that matter. They are there everywhere to draw attention. These guys play with my temperament at times. I am talking about the marketing executives that you find these days selling credit cards, insurance, personal loans and other banking products. These guys broke the rules of marketing completely. You can tell them that you are not interested but they want reasons for your disinterest. You can tell them that you already own one, they come closer to explain the features of their new product. Too aggressive! Given the conditions, banks must apply great strategies to tap the potential. Some 'Sweetie' calls up to tell me what they are offering for employees of MNCs. Some 'John' meets me outside my office/ATM/bank/hotel asking me to spend two minutes to understand the features. This has become too much after all 'Sweetie' and 'John' are clearly told that I am not interested but they continue to come behind. This has become increasingly frustrating! If this trend has to change, it is not enough to instruct these guys but paying less commission by banks may deliver.
*(Names are fictitious)