LUGGAGE TROUBLE Dear Heloise: We haven’t come across this in your column yet! Here’s what to do if the retractable handle of your suitcase suddenly gets stuck and won’t go down, no matter how hard you try to jiggle or force it: This happened to us at Incheon Airport in Seoul, South Korea, a couple of hours before our flight. We were told to go down to the basement where there was a shoe and luggage repair shop. The fellow injected silicone oil into both sides of the handle, and within a minute, he got the handle to slide right down! We hope this fix will save some of your readers the expense o…