That's really something only you can answer.
I once had a house payment not clear but credit to my loan. I called the lender and they insisted it had been paid. My credit union said it had never been put through. Not much more I could do.
Are you sure you put it on Diners? I frequently think I've put something on my debit card, write it down in my check book, think it never cleared and then realize I actually put it on Amex.
As for the double order of pillows being sent ... I've had it happen quite often that a mail order company will send me the items twice. Most often when I call they tell me to keep the second item (usually it's of less than $50 value) because the cost of shipping it back to them and restocking isn't worth it to them.
[This message has been edited by letiole (edited 05-21-2002).]