I dont understand that breakfast and club access have never been a Plat benefit - why would the OP has mistaken such?

He did eat the breakfast, didn't he? He even met the hotel GM at the breakfast...

Then he felt he was misled to sign for the upgrade package which the internet and breakfast alone would cost that much?

Why did he not challenge the bill at check out? This is the part that totally mystify me.

No matter how late I arrive a hotel I always make sure to read what I am told to sign and if it is not very clear I would actually write down my interpretation of the reservation on the card to make it clear what type of reservation that was, especially in certain pre-paid bookings.

It really is the guest's responsibility as well to make sure the information on the check-in paper is correct before signing that.