My parts didn't show up! Neither did my tractor's!

Tool Dept, this is Chris.
Hi, you gave me some part numbers for my tractor and I ordered them online.
OK.
Well I got a message saying they arrived, but they didn't.  May I speak with a manager?
I'm not sure what good that would do.  Our store had nothing to do with it, right?
Well, you gave me the numbers.
Why don't you try calling UPS to get more information about the delivery?
OK.
... (minutes)
Tool Dept, this is Chris.
OK, now I really need to speak with a manager.  UPS was no help.
Well now wait a minute, let's look into this.  Do you have a tracking number?
Yes.  9200190195071300600449.
OK, hold on.
... (minutes)
OK, sir, this is not from UPS, this is a Postal Service tracking number.  Delivered yesterday at 9:30.
Really?  Huh.  I was home all day yesterday.
You need to pursue this through the Post Office or our online customer service.
Hold on a minute.
...
Would you believe it?  They stuck it in my mailbox.