Srisarin

So you claimed for the lack of PAG prior to checkout - therefore your claim is preserved - get CS involved.
That being stated, the lack of PAG often becomes a pi$$ing contest when the property claims you opted for points (even when the offer was never made - easy copout - here in Asia they at least provide a choice via a document but in the US no idea) likely easier to claim under the Plat guarantee for bedding guaranteed but not provided if the double was in fact part of your reservation.