you probably need a new crown/tube set. nothing you can do otherwise. if the tube is non-replaceable (this is a possibility, check on overseas forums first), then you may have to consider getting an OEM tube and crown set instead.
i recommend sending the watch to an overseas watchmaker that is willing to look for both a new tube and crown and knows and is willing to retap the case to install a new tube. there are many.
the ones willing to tap a case in singapore... i can count with one finger, and his rates are too expensive for a watch that costs a few hundred dollars. he also won't waste his time looking for a new tube/crown for you.
if it is common, forums elsewhere may already have a cheap and simple solution to your problem...? try searching first.
“Watches, no matter how much they cost, are better at telling time than making a person happy.” - Thomas J. Stanley