Q. A number of years ago, we bought a refrigerator from a major appliance store and paid with a check. Almost from Day 1, it gave us trouble. They sent out a repairman who made a temporary fix. It failed. Twice more, they sent a repairman who could not get it to work right. We tried very hard to get a replacement, even writing to the manufacturer. All we got in response was a statement that they would repair but not replace the unit. It now works, but sometimes decides for itself to overcool for a day or two. Last month, we bought a new big-screen TV. Fortunately, we charged it on our credit card. When it started to give us headaches, we got the same nonsense from the store that they would repair but not replace. However, the bank issuing the card entered on our side and got us a new TV that works fine. We hope you will advise your readers to use their credit cards for all major purchases. They give you a kind of consumer advocate in your dealings with any vendor.