do I have to refund money if the person didnt file a paypal dispute?

[Skylarr!]

okay, so I sold something, and accidentally left out something. so a little over a month after I sold it, he gave me an email saying he wanted his money back. we agreed just I would pay 100 for the repair. he said okay. now its been 3 months since I sold it. and he never replied once I told him I had the money!!!! its been like a month!! so now that it's been a month,,, I called paypal and they said since its been over 45 days, and no dispute, I don't have to give him a thing. He never replied when I asked him what email to pay him on. so Its been like a month. and today he replied. and gave me the email. and when I called paypal, they had said just to keep the money. what do I do!!!??? im out of work!!