I have tried twice to purchase an irion schematic fro mthe Purveyors of Plans, and while my sp is taken, I have not been given the item on either attempt.
I'm now out of a lot of sp with nothing to show for it! The items have not been credited to my account, because even with a Yunium key, I still cannot make a steamwork pet at Full Steam Ahead.

@ Cornsilk

It's not an instant purchase at the Schematics Shop. Once you've bought one of the Schematics it can take up to 48 hours until the item gets placed in your inventory. It says that as well on the front page of the Shop.

Only one, and I had purchased a second in my confusion, thinking the first never went through... I did get the first schematic though.