Missed the Costco appointment

I just realized that I mixed up the Costco new tires installation appointment date which was yesterday, and I thought it was today..... I tried calling them for half an hour, but can't get a hold of anyone. What can I do ? The next available appointment online will be another two weeks, and I remember it says if the tires arrived the warehouse for more than 2 weeks, they will ship the tires back and cancel the order. Thanks for any advice.