Gokuaku Ganbo

From MangaHelpers:

Kanzaki is frustrated that his failure to graduate high school is still affecting his career options at the age of 27! He consistently gets offered lower salaries than other applicants, just because of his school history. His friend Takemoto introduces him to a different plan of making money-- stealing and copying bank cards! At first, all goes well, but soon Kanzaki learns that they have stolen from the wrong men. After his friend sells him out, Kanzaki is faced with a shady 'conflict resolution' company, which intends to force him to pay for his crimes. First, they send him to a work boat, where there are many men engaging in physical labor to pay back debts, in a situation that reduces them to little more than lifelong slaves. This is absolutely not how Kanzaki wants to resolve this conflict, and he's determined to find a better way. His efforts to pay for his ill-advised crime spree will change his life forever! [tethysdust]