Some owners say they may have to leave their pets behind after a major travel firm raised its prices.
Hundreds of staff will lose their jobs at head office and in stores, with closures starting immediately.
The firm said this month that its founder would sell up to 50 million shares over the next year.
The Australian grocery chief walked out on a reporter when questioned over alleged price-gouging tactics.
Documents show the secret investigation may have helped wrongly accused postmasters prove their innocence.