Banking issue

I was sitting in a cafe where I had a short conversation with a girl. During this conversation, she told me that she would make an online payment to me if I gave her cash in return. I agreed to this and gave her the cash as she asked, expecting the online payment to come through to me. I have not received further details confirming that the online payment was successfully credited to my account, and I am concerned that the transaction may not have gone through as promised. I request that this transaction be checked and verified, and if the payment was not received or turns out to be fraudulent, I request appropriate action to recover my money.