You mistyped the name of the recipient and sent the mail with items/gold attached to the wrong player?
Contact Customer Support as soon as possible.
Customer Support will be able to return the mail to your character as a one-time courtesy only if the recipient has not opened the mail and not claimed the items/gold attached to it.
However, if the recipient has opened the mail and collected the items/gold attached to the mail, in this case, Customer Support will be unable to assist you further and will advise you to sort this issue with the other concerning player.
What if Customer Support took a long time to respond my ticket and the recipient had the time to open the mail and claimed the items/gold attached to it?
Even though Customer Support tries to answer requests in a timely manner, they can sometimes take a longer time to respond due to an increase of tickets. Unfortunately, the item and gold loss from this situation would still be the player’s responsibility as the source of the problem was still on the player’s side.
What options do I have left to retrieve my items?
You can send a mail to the recipient and ask nicely if it would be possible that they return your mail and items/gold back. However, if the recipient refuses to do so, we would still not be able to assist you with this request.