It is not clear what you did exactly. You talk about mdf files, and that is normally not how you restore databases.
However, a common error that people do is that they say:
RESTORE DATABASE db FROM DISK = 'C:\somepath\backup.bak'
and overlook that the backup file includes more than one backup. What happens in this case is that you will get the oldest backup in the file. To get a get a later file, you need to say, for instance,
RESTORE DATABASE db FROM DISK = 'C:\somepath\backup.bak' WITH FILE = 2
You can view which files there are in the backup file with the command
RESTORE HEADERONLY FROM DISK = 'C:\somepath\backup.bak'