Tuan Do of New York says Amazon has banned himfrom shopping on that website.The reason? He returned too many Amazon purchases,he said on his website, TechWalls.com.Do said he returned six items in the past two months.He said he was not satisfied with the quality of the products.Amazon first sent him a warningabout his "unusually high rate of problems," Do said.Later, when his wife returned a bicyclepurchased on her Amazon account,the company cancelled both their accounts, Do said.Mark Cohen is former chairmanand chief executive officer of Sears Canada Inc.He is not surprised Amazon and other businessesare trying to stop frequent returns.The costs are very high for a company like Amazon that offers many customersboth free delivery and free returns, Cohen told VOA.The website Dyanamic.action.com reportedthat returns cost merchants $642.6 billion a year worldwide.But banning a customer can create bad feelings.Greg Nelson recently spoke to the Guardian newspaperafter Amazon UK banned him from its shopping website.Nelson said he sent back 37 of the 343 items he bought on the website.He said he had a good reason for each return."I could understand if there were evidencethat I had somehow tried to abuse the system,but I haven't," Nelson told the Guardian.Amazon said it only closes accounts "in a tiny fraction of cases"when it finds "extreme account abuse."Cohen, the former head of Sears Canadaand now a Columbia University professor,said many returns are valid.It is fine to return clothing that does not fit,is the wrong color, or arrived damaged, he said.But there are many cases of "clear abuse."Cohen cites the example of people who buy a dress or suit,wear it once to a wedding or other special event, and then return it.Cohen said Sears Canada had a customer who bought itemsfrom the Sears Catalog all the time – and returned every single purchase.Cohen said it seemed the customer wanted something to doand enjoyed placing orders, getting them delivered and sending them back.Cohen said he had to convince his staff to ban the customer.Some staffers said a ban did notfulfill the company's promise to "completely satisfy" customers.He helped write a letter to the customer.It explained she could no longer shop"since we clearly have been unable to satisfy your needsas much as we have tried."Cohen had won the argument.On his TechWalls website,Do said he bought "almost everything" from Amazon.That included cheap items like groceries and toilet paper,and more expensive items like laptop computers.He said the returned items costs more than the products he kept.But he said he only returns products"when they don't meet my expectation."Do had some support from his online readers."Bob" wrote that he, too, was banned for too many returns."It was a crazy high percentage in one bad month.But, yes, they were all defective.I wasn't abusing/trying and returning," Bob wrote.Cohen said online businesses like Amazonare getting hit with more returns than traditional stores.One reason, he said, is that shopping onlinedoes not allow customers to try on clothingor take a close look before buying.Many products, he said, are returnedafter they have been taken out of their packages, often in bad shape.In the case of clothing, he said,returns often come in after the selling season ended for winter or summer.That makes them hard to sell,or forces big price cuts, Cohen said.