Geeta,
If an employee is not willing to accept increment, then its not your problem..unless he/she would not accept the clause/letter formally(duly signed with)..he/she won't be entitle for revised pay scale...however everyone is working for money
You can formally announce on email, after that your part is over & ball is in different court. you can justify to management that i have done all formalities and this a formal email regarding this but i have not received any inputs from employee.
Hope i have answered your question...Thanks
Regards
Deepak