I'd start by asking the member if they have any more information about the canceled sealing, such as an approximate date. Or better yet, a letter. I'd also try to (carefully) elicit any additional information such as the circumstances. There's a possibility he's not understanding the situation. For example, if he's been sealed to another spouse, that doesn't cancel the first sealing automatically. However, the First Presidency would have to approve it and the prior spouse would have been contacted. (See Handbook 1:3.6.1)
Typically, a sealing is not canceled unless the wife finds another to get sealed to or there's really bad blood between them.
Then I'd contact support and see what they can see on their end. Note, there's nothing you can do to change things, all you can do is facilitate the flow if information for CHQ to make the changes.
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