Your friend and her father owe you the value of the bicycle that was improperly sold. You were given permission to leave the bicycle at her house. She and presumably her father know you. They made no attempt to have you pick up your bicycle. They did not turn the item to the police department as an abandoned object.In essence, your friend and her father improperly sold your bicycle. Some people could consider their actions as a "theft" of your property.You need to speak to your parents or an adult you trust about what happened. You have a case to sue your friend and father in small claims court over the loss of your bicyle.