Mad Max: Fury Road (2015) director George Miller and his producing partner Doug Mitchell are suing the Warner Bros studio for not paying them a bonus of $7 million.

The dispute explains the delay in two planned sequels to Fury Road, which earned an estimated $379 million worldwide, was one of the best reviewed movies of 2015, and won six Academy Awards.

Miller and Mitchell were reportedly promised a bonus if they completed Fury Road below a budget of $157 million. Miller claims that the budget overruns were not because of their actions, but because of the studio’s own decisions.

“Simply put, we are owed substantial earnings for diligent and painstaking work which spanned over 10 years in development of the script and preparation and three years in production of the movie,” Miller and Mitchell told Sydney Morning Herald. “That hard work resulted in a picture which found wide acclaim globally… We would much prefer to be making movies with Warner Bros. than litigating with them but, after trying for over a year, we were unable to reach a satisfactory resolution and have now had to resort to a lawsuit to sort things out.”

Warner Bros is contesting the claim, which was filed in a court in Australia on September 3.

Mad Max: Fury Road (2015).