Here's how it works at the Napa I work at: There's only one warehouse that's local that we order from. We send a driver a couple times per day to pick up parts at the warehouse. So, if you order parts in the morning, you'll get it the same day. If you order late in the day, we have the parts overnighted and they'll be waiting for you when we open at 8 AM the next day. If the local warehouse doesn't have it, it's considered a special order. We order from the next closest warehouse, make you pre-pay, and charge you about $5 shipping (hey, UPS doesn't work for free). Usually it takes 2-4 days at the most to get parts from another warehouse, depending on how far away it is.
Ask them WHERE the parts are coming from. Sounds like they're pretty incompetent.
All NAPA's are NOT created equal! The NAPA around here, orders from the local warehouse, and they do NOT "special order" from other warehouses, it just takes longer for the items to arrive, at no extra charge. If you order before 10 a.m. you can usually get it the same day, if the local warehouse has the part. Also they have AAA discounts. They also have bar stools for the patrons!
They hold your items for up to six days, then they send it back "on the truck". The people that work there have classic cars themselves. They are into cars, drive them around town, and it is great that NAPA supports this.
But my NEW alternator recently came in a shotty box! I told the dude, "Dude, open that up, make sure it's ok, that box looks like it's been well worn"
It was good. NAPA seems to not sell CRAP, AutoZone is REALLY, Really bad at that, cheap crappy fuzzy dice, and Made in China Isles with Fuel saving scams like the Turbonator, etc.
O'Rilley's is better than an AutoZone, the store, the people, generally look better, and you can pay at the counter rather than the "checkout zone" that never has enough change.