Spent weeks prepping and teaching a friend everything they need to do a job for a vacancy at work. The role was already arranged for a higher ups son months ago.

I've gotten annoyed with work plenty of times but this has just broken me. These people lied to my face for weeks knowing I had a friend who I really wanted to help out, taking advantage of us and our free time. Seems so stupid, why not just say we already have someone in mind for the post. Do they get off on the false hope? Best part about it is the email saying what week I'll have to be on site to train the new hire. Not really sure how to answer it or what to do now. Am I supposed to just go about my day and ignore the fact I work with these aholes.