One of my customer said he has received a wrong product size, and however my shipments are still in receiving process and cannot demand an investigation, do you guys meet this situation before and how to fix it?
Always assume FBA employees are blind. They are on timers, and know nothing of your product.
You have to wait for your items to be received. Your items are not simply sitting in one location for someone to fix, they are in transit around the country. If you feel it is a labeling issue, it may be best to close the listing until you can get it sorted out.
I would not rely on one buyers return reason to believe there is an issue.