I am using GUI 18.1.2. A few weeks ago, I got 2-3 extra Monero in my wallet (without doing anything). The day I saw it I successfully performed a transaction.
Now, a few days ago, my transaction did no get any confirmations and after having the status "sent(pending)" went into the status "send(failed)". I therefore followed all the steps here (and some similar instructions) and also tried a remote node: Transaction stuck as "pending" in the GUI
Now I cannot even submit a transaction but I am stuck with the error:
Could not send the money. Status:Failed. Reason:double spend, invalid input
Do have any suggestions on how to get back in sync and also drop the wrongfully obtained Monero?