Joni,
Your problem may very well be the FrameSpace that was used to keep the print off of the glass. Depending on which FrameSpace was placed in the frame package, it may not be applying any pressure at all to the print. Some of the FrameSpace profiles aren't made to hold a print in place at all, just supply some working room and space between the glass and image for the mats/mount to fit without touching the glass.
I would consider talking to the customer about matting and completely redoing the print. Redlins aren't made to be framed without mats in my opinion. With that wide white border, it must look very generic with no mats on it.
I would suggest using Preservationspace I or Econospace or the solid spacer made by Arlo if they don't go for a redo. These are stronger than Framespace and will hold the print in place better than the thin walled Framespace.
Keep in mind that, with the print already buckled, you may not have much luck with anything you try until you get the buckles out of the paper which isn't always an easy task.
Good luck.
Framerguy