It should have been obvious in the first place. If the transaction was done correctly, there will be no issues but I think there was miscalculations in your part.
When we are doing online transactions we first should have our checklist so we can spot red flags. Here is my own (I am open for changes or correction)
1. The platform should have a way of tracing identity for accounts (This can be helpful in a way because you can physically chase the perpetrator) one example is contact number.
2. If the deal is in "Money first system"(sometimes its not the case), it is automatically red flag, especially if they are upfront talks about the amount and they are not building rapport with their transaction.
3. Review the platform, if there had been testimonies of scams happening at that platform then it is another red flag.
4. If possible, make the transaction a meet up in the real world(this might be unlikely because we are talking about online transactions). Cyberspace is not our enemy nor our ally, it depends on how we use it.
5. Check for the profile of the account if there were past transactions.(Duh!)
6. Use legitimate and trusted websites where you can still appeal and get help when a scam happens.
7. Use your common sense, if its fishy just peace out.
That's all, again I hope this will help so no one will become a victim. (Feel free to add something to the list just quote this, and for translation just message me.)