Termination Of Employment - Salary More Than RM5000

Hi,
My company had terminated an employee who earned more than RM5000 due to his unsatisfactory performance and breach of professional practice as he miscarriage of company petty cash for few thousand.
However, my company has agreed to pay for his salary for the month that he worked and another 1 month compensation (according to our company policy, resignation notice is one month). He had agreed by signing the termination of employment letter.
Despite that, he insist to make claim to industrial relations department and decline to receive the one month compensation.
Can anyone advise me what can I do and percentage of winning chance is big?
Thank you so much in advance.

dear karen
your question is not clear as in are you terminating him or is he resigning form job ??
first go for your company standing order...if tis falls under the major misconduct then you can terminate him completing the paper procedure for chargesheet.
and if possible coordinate with ur company legal dept on tis issue.

Hi Sweety Shah,
Actually we are the party who terminating him by giving a termination of employement letter. He has signed and accepted on the letter. But the other way round, he sue us to Industrial Relation Department and declined our compensation.
Attached herewith the sample of letter for your kind reference.
Thank you.