How was I to be aware that you had already generated the list?
You did not tell me you had already done it. We were discussing payment.
I received a PM after that with the list done for free.
I do not believe that I have scammed you in any way.
You made a promise:
Let's make it 0.25 BTC.
Based on this promise the user worked to satisfy your request:
I have yet to received payment, and I have the list for you.
You failed to keep the promise:
This guy did it for free
If you did not wanted to pay, you should not promise to pay. You defrauded someone to work for you without the intention to pay.