Pressure from new African nations admitted to the UN after successful insurgencies during the period of “decolonialization” in the 1960’s eventually compelled the UN to revoke South Africa's Mandate in 1966; it was of course ignored by South Africa, who were then subjected to embargo by most western nations, including the USA, for this and other reasons. In 1973 the UN took the step of recognizing the South West Africa People’s Organization (SWAPO) as the Namibian “government,” although the land remained under South African control in defiance of the UN.
SWAPO was a typical gang of Cold War Communist stooges, with the usual hyperventilating rhetoric and bullshit associated with Communists world wide. SWAPO, assisted by South Africa's African National Congress (another Marxist organization) and their friends and fellow travelers in the UN and the Soviet Union—and not a few in the USA, whose embargo lasted well into the 1990's—waged a prolonged, violent, and ultimately successful effort to oust the South Africans. After a protracted insurgency and substantial bloodshed, in 1985 South Africa set up an internal Namibian government and concluded a “peace agreement” with SWAPO under whose terms the country would hold “free and fair elections.” Both sides agreed to accept the results, whichever party won.
Needless to say, SWAPO had no intention of playing by the rules, nor did they: the elections were blatantly rigged so that even though SWAPO had lost the war (there was never any chance they could achieve a military victory) by chicanery they managed to win the peace. Today SWAPO is the ruling party (there aren’t any others, surprise, surprise!).