Selling Fun Run accounts is against our rules and Terms of Service
1.1; You shall not have more than one Account at any given time, sell or give away your Account, create an Account using a false identity or information, or on behalf of someone other than yourself; *
Accounts that are sold, will be deleted and no one will have access to the account anymore. We will not be able to help you recover a deleted account.
If an account is suspected sold, and two players are arguing about the ownership of an account, there is a chance that both players will lose access to the account as a measure to prevent the potential sale/scam that is occurring.