Lowe's

I placed an order for 10 cases of DRICORE Insul-armor sub-floor panels on 4/25. At the time of the order, there were 10 cases in stock (according to the website.) On two occasions since the order, I have received e-mails informing me that the order has been delayed. My current estimated delivery date is 5/25. In the mean time, I have a large pending charge taking up space on my credit card.
I have called the local store that is supposed to be fulfilling the order. They could only tell me the new delivery date (which I already know), not why it is delayed or if I can expect further delay. They also say they cannot cancel the order either because it is being delivered to my house.