It seems the backing plates are a rarity. Min. $200 for a single new puts them out of reach for me so I'm looking to buy used if possible. They are available in Canada for $50 but I can't anyone to ship internationally. I'd hate for a simple part like this take my beloved Vibe out of service for good.
Reach out to our Canadian members on Facebook. PayPal them the money, shipping cost, and a few bucks for beer, and they'll get it to ya. In fact, a few are planning to meet up in Erie, PA first weekend of October so they could easily bring them over and ship them for you.