Australia: See the Federal Police website
Canada: Visit the Canadian Standards Association (CSA)
Denmark: The Danish Patent and Trademark Office
Europe: EU Commission customs website
Finland: Finnish National Board of Customs
Hong Kong: Customs
India: Central Board of Customs and Excise
Japan: Japanese Customs
Korea: Korean Customs
Malaysia: Malaysian Customs
New Zealand: New Zealand Customs
Pakistan: Pakistani Customs
Russia: Russian Customs
Singapore: Singaporean customs
South Africa: South African Customs
Thailand: Thai Customs
UK: Contact Standard Trading Offices
USA: U.S. Customs and Border Protection
Counterfeit phones are manufactured illegally and in most countries it is illegal to sell them. Counterfeit phones are produced to deceive consumers into thinking they are genuine.
If you have purchased a fake phone by mistake then you should attempt to return it from where you bought it for a full refund. Then you should report the counterfeit sale to the police, the genuine brand owner and any relevant authorities as soon as possible.
If you have bought the product online then you should attempt to contact the seller to arrange a refund and then report the counterfeit sale.
To report suspected counterfeit or imitation Apple products, contact: firstname.lastname@example.org.
To report suspected counterfeit or imitation Motorola Mobility products, contact: email@example.com.
To report suspected counterfeit or imitation Nokia products, contact: firstname.lastname@example.org.
To report suspected counterfeit or imitation Sony products, contact: email@example.com