Keep in mind, OP, cancelling a card that already had charges is only cancelling an active card, not the application for a card. So, bottom line, the inquiry WILL be on your credit report and, in my opinion, you want that card to remain open for a month or two before you pay it off and cancel it. Otherwise, you will have an inquiry without a resulting trade line. If you keep it for a month or two, pay it off and, then, cancel it, you'll have a trade line showing paid as agreed and closed by customer. A much better outcome for your credit report.
Yes, I understand you didn't want the card at all. But it's done and you should be focused on your credit report.
Ps: If I understand you correctly, you already cancelled the card which precludes any further charges. What I would do is keep your stuff and pay for it... half this month, half next month. It might even be more prudent to split it into three monthly payments. In my opinion, this will be much better for your credit report.