The reasonableness of the matter and reasonable amounts are two major points.
If the establishment has not spent on specialized training that added to some extra ordinary skills and qualification of the employee the establishment may not succeed in its claim.
Did the employee join as an apprentice under Apprenticeship Act or Graduate Trainee as per some training scheme in line with standing order of the management?
If the employee joined as Graduate Trainee/Apprentice it should have been properly mentioned in appointment letter issued to him.
The guidelines in such cases are explained in “Apprenticeship Rules, 1992”........................
If the employee joined as Graduate Trainee as per some training scheme in line with standing order of the management the employee may demand certified copies of the standing orders.
Employee is bound and under obligation to display standing orders at a conspicuous location in company/notice board, and supply the certified copy to the employee against a nominal fee say Rs.10/-.
Employee or any one can obtain the certified copy of the standing orders applicable to the establishment from certifying officer (CO) against a set fee say Rs.3/page. The Certifying Officer may be DLC in o/o Labor Commissioner at the location of redg. office of the company.
Employer himself is responsible for faithful observance of standing orders.
You may show the job advertisement, job application, interview call letter, offer letter, appointment letter, standing orders applicable to the establishment (Certified/Model) and extended to the designation of employee, letter to join training, curriculum of training-name and content of course, certification of the course issued to employee, Provider of training (internal/external), detail of boarding lodging provided for training ( in hotel or own guest house) , expenses incurred, HR policy, service rules, Bond/service agreement, etc to your labor consultant/service lawyer.
Your lawyer that has seen all docs and has analyzed the inputs can advice you the best.
There is a possibility to negotiate for pro rated payment of compensation.
However it shall be better to proceed once you have understood the merits from your lawyer.
IN the meantime you may find the attachments as useful.