I assume the following,
Client AND Server has backups on a daily basis?
I also assume that the client has now the corrupted and missing files, but at this point the non-replication hit and the server has a version of * days earlier (the time the replication stopped)?
So why does the customer not have a look at the modified date of their files?
If there are incremental backups, I'd do a browse and restore on jobid-level (Not on Backupsetlevel - have a look at the jobhistory of the subclients). There you have all CHANGED Data.
Maybe also you could use "Show deleted Items" in the Browse-and-Restore on the Backupsetlevel..
Please provide further details if not solved yet.