I'm extremely sorry that you were misinformed by someone at Adobe, but there never was a plan for migrating any data -- files or tracking data -- from SendNow to Adobe Send.
We had multiple email announcements to all SendNow subscribers that included this:
On January 6, 2015:
• SendNow will be fully retired, and you will no longer be able to access files or use SendNow.
• Previously sent SendNow files, and all associated information, will be deleted from Adobe servers. Recipients will no longer be able to download files.