There are two key things you are forgetting Jordan:
1) The customer is always right. Especially when they can call your boss and get you fired.
2) The Americans with Disabilities Act (ADA). While it's a little blurry as to whether this applies to you, it's not something to fuck with. The government has NO sense of humor when it comes to matters of businesses not making concessions for cripples.
A bit different for paper boys, moreso considering you put the tube by the existing mailbox, but they could still make life suck for you.
Oh, wait, they did.
A little thing called "Customer Service" might have helped you here....