It seems the online ordering and curbside pickup program still has some bugs to work out, unfortunately at the expense of the customer. I see inventory discrepancy quite often when I check stock online and head to the store to find the item not in stock. Checking online again it still says it's in stock. Not sure if there is a lag in the inventory system or what, but my guess is they are selling more than they have to cover the potential that people cancel or dont pick-up orders. Hopefully this will get worked out soon because what you are describing has happened to me a couple times at home depot and other stores.
I would call up Home Depot, I don't think they monitor this forum.
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