How to Reserve an Item Online

@Ian Ok thank you.

How long do you normally hold an item(s) after the confirmation email is sent?

Is it possible to change an item from the reservation once it is made?

So if I were to make a second reservation with the first one still intact would I be able to cancel the first on or just tell them that I’m only there for the second reservation I made while I’m in the store

I have a $25 coupon for in-store use only that I'd like to use. If I reserve something online, can I bring the $25 coupon in to adjust the price?

Is there any way to reserve a sold out item? I'm trying to build a PC and 3 items are currently sold out and there's no reserve option. How often do stocks get replenished in stores?

Is there an email or number to contact about an online reservation issue that is not store level?

Basically, used online reservations many times with no issue. Then, I recently did it with a release day item and got a confirmation that the item was ready for pick up. Got up there in my pickup window and the store says there is no reservation with my Name or Reservation Number on it and that they can't even pull up the Reservation Number. The item was clearly sold out then, so they couldn't just run back and get it. I even got emails still reminding me to pick up after this failed pickup. Basically, they say there is nothing they can do. 

I'd hate for it to happen to someone else or me again. This is the kind of incident that makes me more likely to use online stores. I had planned to grab a CPU and Mobo, which after this, I choose to purchase from Newegg.