Followed Dell Support; 2 orders were made and I need to cancel one

I purchased a 38" ultrawide monitor from Dell a couple days ago. However, because there was a billing and shipping address mismatch, the payment failed to go through. The website told me to contact Dell Support so I gave them a call. The representative said she can help me resolve this by paying through a new quote that she generated over the phone. The quote worked and my order was successfully placed.

Today, I noticed that the original order automatically retried and ended up going through. I assume by calling the agent to pay, I paid for the original order, but instead I actually paid for a second order. The agent or system did not cancel my original order even though the second one went through.

Now I have two orders placed for the same item and I would like one of them (the latter one) to be canceled. There is no option to cancel on the website.

How can I get this resolved? I do not want to be charged a 15% restocking fee for an issue that was caused by the system and outside of my control.