Would you mind giving a breakdown of how many hours you worked and your per diem rate of pay? IIRC it is $20 an hour for the first 70 hours. That equals $1,400. You claim to have grossed an extra $2,600. Even if we were to assume that your per diem is $2.00 per hour, you would have had to fly almost 150 hours to gross $4,000.
70 x $20 = $1,400 (base hours)
70 x $2 = $140 (base per diem)
76 x $30 = $2,280 (overtime hours)
76 x $2 = $152 (overtime per diem)
Total = $3,972 salary and per diem for flying 146 hours.
OK, maybe not starvation wages, but definitely slave labor.