According to the concluded student agreements with OAO

According to the student agreements concluded with Uralvagonzavod OJSC, Dobrynin, Derbenev and Dubrovin (an employee of the OJSC) undertook to work for a certain period after receiving the appropriate special education in this organization, and OJSC to provide them with work in the specialty they received.
Dobrynin needed to work for five years, but within a month after receiving an education, the employer did not provide him with a job in his specialty, promising to provide him after three months (when the employee will be dismissed at the end of the employment contract). Dobrynin refused to wait and got a job in a specialty in another organization.
Derbenev was supposed to work for four years at the OJSC, but after working for three years, he made absenteeism with no good reason and was dismissed under sub. “A” p. 6 art. 81 of the Labor Code of the Russian Federation.
Dubrovin, having worked for two years out of three and a half years, filed an application for dismissal of his own free will in connection with moving to another locality (part 3 of article 80 of the Labor Code of the Russian Federation).
OJSC raised the issue of recovering from them the costs associated with training, because they violated the contract (did not work out the deadline).
In what cases and to what extent can an OJSC rely on reimbursement of training costs for employees?