Save Mimi leg my American Bulldog

This is a horrific medical error, my puppy Mimi went to the hospital for broken back leg bone, she was placed in a cast and clinic asked us to return 3 weeks later when we took back the cast fell off to expose her foot decaying the Doral Animal hospital refused to acknowledge there mistake we were transfered to MVS specialist where we quoted a estimate to save leg at $4,000.00 to $6,000.00 please help so that Mimi can keep her leg and won't be amputated to verify please call clinic [phone redacted] she is at 8601 sunset drive MVS hospital