Mixed up results can certainly happen! My late mother was erroneously told that she had a recurrence of breast cancer after hospital tests, it was two years later when a young, on the ball doctor questioned the diagnosis that she was told that it hadn’t recurred. Quite apart from the worry caused to my mother and her unnecessary treatment, what about the poor woman who was told that her test was clear?
In your case, OP, I would contact the clinic again and ask for a review.