Employee service bond

Dear Team, I have signed one sided bond for the period of 18 months and if fail to serve then to be liable to pay 1.50 lacs to the company. I have travel for foreign country for process migration/transition on behalf of which I have signed bond. Currently I am on notice period & will be completing 16 months till last working day. On the basis of that I have requested the company to take bond amount of Rs. 16,666 on proportionate basis for the rest of 2 months of bond period. But company is not agreeing on it and they are asking me to pay the complete bond amount of Rs.1.50 lacs. Company even hold my salary for last month & they are asking me to provide postdated check of Rs.1.50 lacs as security to release the salary. According to the bond condition an employee should provide cheque against bond amount before one week from last working day. I will be in the company for next 20 days so I informed HR about this but they are not listen to it. Please advise how I deal with the situation and provide quick remedies to get rid of this problem immediately. Also provide some contact number where I can raise this issue.