None of us can answer this question, which is why you need to speak to the school and find out what happened.
It's not a great example, but my dd has told me her dad wouldn't pick her up and she was forced to walk home, and when I've checked with him, she's actually said to him, "Will you come?" and he's said "Yes, in half an hour when I finish work" and dd replied, "It's fine, I'll walk." and then relayed to me that he wouldn't come and made her walk. Not that he had said he would but she'd just have to wait.
Anyway, point of that is, had I just accepted her version, which was true to HER, then I'd have been really pissed at her dad, but after I asked him, then her, she said, "Well, yes, I did say that, because he wouldn't come!" and we then had a conversation about the full exchange.
You need the information, then decide what to do.