What I would do is contact the card issuer first, and explain what happened. See if you can get a statement in writing with contact information from them to detail the mistake, then file a dispute with Transunion. The reason I suggest doing this is it makes the dispute so much faster when you have the documents and contact information available if needed. You could also just dispute it without this too, sometimes they will see that the same company made a hard inquiry twice in a short period of time and correct the problem anyways.