I Need Help Regarding An Online Order, The #1-800- 591-3869 Didn't Help

No one can assure me that my large order is going through, things on back order now that was in stock, placed my order on line 5 days ago and they keep sending messages to retry or re enter another payment method.  Have re entered, got confirmation, called them twice, still getting messages to re enter payment and no one can tell me why.  My bank says everything is ok.  My debit card works fine, have enough money, don't understand the problem.