Firstly, I would suggest that you do NOT go into this, with ANY expectations (ie. expecting an apology, acknowledgement of wrongdoing; or, even that they'll listen). They COULD, very well, try to turn it around on YOU, and blame you somehow, in some way.
Secondly, if you ONLY just want it to be known that you know what they did (meaning, you have NO expectations), I would suggest just simply saying: "I just wanted to let you know that I consider what you did, to be your using me----and, it will NOT happen again." Then, if they start on some crap about: "No, you misunderstood", "No, it wasn't like that", "Well, I wouldn't have done that, if you hadn't...", I would just put-up my palm (as a Stop sign), and say: "I've spoken my peace", and then turn on my heel and walk-away.
It CAN be successful----I've done it, myself; and, I was very lucky in that the person didn't even try to fight me, on it.
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White female; age 59; diagnosed Aspie.
I use caps for emphasis----I'm NOT angry or shouting. I use caps like others use italics, underline, or bold.
"What we know is a drop; what we don't know, is an ocean." (Sir Isaac Newton)