It's always annoying when a buyer retracts a bid - I always add such bidders to my blocked bidders list.
Your item is set up to send to UK only so it is likely your African buyer will want the item sent to a UK address.
If that buyer pays, and it is a UK address - most likely a freight forwarder - there is no reason not to sell to the successful bidder.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)