Yes, the procoptodon goliath had predators. The Varanus priscus (a very large lizard) and the Thylacoleo, better known as the marsupial lion, were predators of the procoptodon goliath.

Like all kangaroos, Procoptodon lived in Australia.

The Giant short faced kangaroo became extinct because of loss of habitat

There was once a giant kangaroo, now known as the Procoptodon. It was one of the many species known as Australian megafauna, and became extinct thousands of years ago. The giant kangaroo no longer exists.