Seizure and Lesotho registered vehicles by traffic officials and Customs officials in the free state

Hello Peter, a month ago my wife's sister in law from Lesotho borrowed her, her car, Lesotho registered, to run some errands when she came to visit her husband in bloemfontein, she possess a valid South African driver's license and the vehicle is also road worthy, she was stopped by traffic officials and the vehicle was siezed and handed over to Customs which in turn requested vehicle ducuments to proof that the vehicle was not imported to South Africa *******ly, her sister in law provided them with the vehicle ownership documents and a copy of her valid passport, but they are still refusing to release the vehicle and want them to pay a fine of R2500, for what good reason, we just don't understand, that's her sister in law's personal vehicle and she stays in Lesotho and she doesn't not intend to import that vehicle to South Africa any time soon, I think this is absolute abuse of power by the officials with the intention of abusing state resources if any litigation is put against them and with the knowledge that most people can not be afford to sue the state. Please assist