The immigration laws of most countries do not have provision for appeals. Your own government cannot help you and border guards are not necessarily gentle in carrying out their duties. A form of permission for a non-citizen to travel to, enter, transit or remain in a particular country. A visa does not guarantee entry. That decision remains the right of the immigration officials of the country concerned.
Some countries ask visitors to present return tickets and evidence of funds to cover intended stay.
Some countries refuse entry to visitors who do not comply with their requirements regarding general appearance and clothing. Some countries refuse entry to visitors who are HIV positive. Some countries have compulsory currency exchange regulations on first entry. Deportation is at the traveller's expense. The validity and type of visa issued must be strictly adhered to.