JOE BAVIER and MaCDONALD DZIRUTWE HAVING fled an economic implosion in his native Zimbabwe, Brighton Takawira was able to support his mother back home with modest earnings from a small perfume business he set up in South Africa. Then the pandemic struck. Borders closed. The buses he had used to send his cash stopped running. "I had to send something, even a few dollars," said Takawira, though it meant sometimes going without bread. So he tried out an online remittance company on a friend's recommendation. He is one of many African migrants being pushed towards digital transfer services, often for…