I think there were problems getting money out of the country for BA. The ZW$ became worthless, prices were doubling every day there were shortages of fuel.
BA had wanted to withdraw earlier than they did but were persuaded by the British government to keep operating so that their citizens could have an escape route.
The country is a failed state. Most of those with the means to leave; money, skills, foreign passport have gone.
White population numbering close to 300 000 at its peak during the 1970s has dwindled to around 30 000 mostly ageing. Skilled black population have departed for the UK and South Africa, unskilled locals flooding across the SA border to work on farms or beg on the streets.
A crying shame, a beautiful country with so much potential destroyed by one of historys worst dictators.