My Amazon Order Has Been Stuck Delayed Since May 15

I placed a standard Amazon order on May 13 with a scheduled delivery date of May 15, under order number 111-4903427-5975422. My order contains two items. Throughout May 15, I waited for my delivery, and only very late in the day did the status finally change to indicate that there was a delay. No explanation was provided about the reason for this delay; there is no indication of which of the two items caused the problem, and there is still no new estimated delivery date shown in my account. I have also not been able to reach anyone from customer service to get clarification, which is increasing my frustration because I simply have no information to plan around. I request that Amazon clearly explain the reason for this delay, specify which item is causing the issue, if applicable, and provide a precise and updated delivery date. Once I have this information, I will be able to decide whether I want to keep the order or cancel it and request a refund.