this happened to me at the DT in Memphis. Perhaps the experience of the desk staff has something to do with whether or not you get one. The desk clerk first thought it was a direct bill and could not give me a copy of the receipt, but after explaining it was pre-billed to my credit card, she was able to work around whatever issue there was and give me an itemized bill.
Perhaps asking for someone higher up to work on this for you might yield better results.

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