Olx Autos — Olx sent money for second hand car without document signing

Hi there, I have a situation to be sorted now with olx autos. I would need your help in this.
I wanted to sell my car and i had booked for a car inspection. I got a quote from olx and I had provided my documents. I haven't yet signed the sale deed.
I have decided not to sell my car now.

I already received the payment from olx without me signing the sale document.
I also haven't the token for my transaction.
How do I send back the money ?