I had a booking with the Meridien in Lisbon on a non-refundable rate made only days before the announcement that this property was leaving SPG. I did receive full SPG credit even if I did not get a room upgrade. Most importantly I did get the final of my 7 Meridien stays for the 4 free Meridien nights promo. This was all resolved on my behalf by Starwood Corporate so I would be confident that they will resolve your issue.