Just an update:
The seller contacted me back and explicitly told me that he refunded my money because he discovered it was a SP. He was apparently tipped off by another Pietrangelo collector (I have a feeling I know who it is but I won't say any names) who offered him $40 for it. Honestly, does this hobby really need to be that cutthroat for a stupid hockey card? The gimme, gimme attitude with some collectors is absolutely ridiculous.
Anyways, the seller offered it to me for $25 which I accepted. I'm still going to report this seller to eBay since I'm fairly confident that holding an item hostage is against eBay policies.