Roger Gilbert, 76, was chief executive of Fujitsu s UK and Ireland business from April 2009 to 2011, during a key stage in the development of the scandal.
Jacquie El Kasaby and Rose Stewart were told they would be pursued by debt collectors if they did not pay up, despite not taking any funds, BBC Scotland reported.
The Post Office continued to threaten two sisters over a £34,000 shortfall even after a criminal trial was ruled out over faulty computer evidence, the BBC has learned.