They probably weren't sent to corporate.... prolly just didn't answer the phone so it forwarded to call center. Corporate does not get forwarded calls directly from stores they have better things to do.
An all orders drinks if they were short handed.. at a lame franchise... they deleted it cause they didn't wanna be bothered. You can go with the prank theory. Lugging a bunch of heavy drinks we usually have to give drivers a little push for that.
I tell businesses to make a note on the order with a company name and a personal contract name. This triggers the store to know its a business order which overrides negative assumptions
If your number was new to their system its company policy they should have called before delivering it, which is why I'm going with lazy employee syndrome. I've got 15 years in the industry it smells of "15 drinks F that" Ive fired people over it.