You’re obviously a good person, as evidenced by the fact that you’re asking this question. True, the jobs weren’t guaranteed, but looking at the contact, as others have said, will let you know if you had an escape clause (pun intended

), and lawyer will be able to help you understand if you technically DO owe the money back. As another user said, the interview offer complicates things.
My disclaimer at this point is that I’m merely speaking for myself and from my own experience: the fact that they have not made an effort to come after you suggests that they were taking a business risk by financing students and have decided to eat the loss. I assumed from your post that they haven’t come after the others either. Be aware, though, that as another user said, they may come after you at some point in the future, like maybe when your wife is pregnant with your second child, you’re out of work, and have a mortgage. Call a lawyer. In my own experience, they love to talk to you even for free just to see if they have a case and have never failed to give good advice even in a free phone call. Reiterating my disclaimer, I’d think that the letter of the contract would stipulate _n this case whether or not you’re
morally obligated to pay it back.
Saint Joseph, you devoted your time at Nazareth to the work of a carpenter. It was the Will of God that you and your foster-Son should spend your days together in manual labor. What a beautiful example you set for the working classes!
It was especially for the poor, who compose the greater part of mankind, that Jesus came upon earth, for in the synagogue of Nazareth, He read the words of Isaiah and referred them to Himself: “The Spirit of the Lord is upon me, because He has anointed Me to bring good news to the poor…” (Luke 4:18). It was God’s Will that you should be occupied with work common to poor people, that in this way Jesus Himself might ennoble it by inheriting it from you, His foster-father, and by freely embracing it. Thus our Lord teaches us that for the humbler class of workmen, He has in store His richest graces, provided they live content in the place God’s Providence has assigned them, and remain poor in spirit for He said, “Blessed are the poor in spirit, for theirs is the kingdom of heaven” (Matt. 5:3).
The kind of work to which you devoted your time in the workshop of Nazareth offered you many occasions of practicing humility. You were privileged to see each day the example of humility which Jesus practiced – a virtue most pleasing to Him. He chose for His earthly surroundings not the courts of princes nor the halls of the learned, but a little workshop of Nazareth. Here you shared for many years the humble and hidden toiling of the God-Man. What a touching example for the worker of today!