Why is my order on hold?

Hello Team Support,

I received an email saying something like this: "If you receive an Order Held email, it means that we couldn’t obtain authorization to process payment for your order. " On the email said that I need to contact them. I contacted them and they said there is a code to confirm verbal authorization. Where can I find that code? I got some paper mailing to my address. Everything in the envelop is the agreement and welcome. There is no code to do the verbal authorization. Who should I call to proceed to the next step for the order number and shipment date? I am a bit confused and frustrated. I wish Dell support have steps to do when I am a new customer and trust to apply to finance for buying dell products. Thanks.