I agree with Caz that there was likely no "had to" about signing this Bonding agreement.
Legally, the signee was probably (properly?) informed of the intent and implications of signing, and signed it, taking the then perceived benefit of attending the course and thereby enhancing his/her future career.
This situation is no different from any civil case of Bonding Agreement that I've seen.
Unless the signee can indicate an error in the offer and signing process the outcome is almost inevitable.
In most civil cases brought to court the signee has had to pay his/her way out of the "agreement" (a pro-rata payment) - or their future employer has voluntarily paid it, and the signee ends up in the same situation but with another employer.