Service conditions are stated in standing orders (certified/model) applicable to the establishment and extended to the designation of employee, appointment letter, HR policy/service rules and regulations mention of which is made in appointment letter.
Standing orders (certified/model) being instrument of law/statue shall prevail upon any private agreement that employer might have signed with employee e.g; appointment letter, contract of employment…………………………etc
Being Director Model Standing orders should not apply to you. Company might have not framed its standing orders and might not have included your designation in it.
You may download and go thru service rules and regulations mention of which is made in appointment letter.
The notice period for senior management can be from 3-6months depending upon the service rules and regulations/HR policy of the establishment. If it is stated then it should be the min. compensation.
The severance package may be negotiable. You may apply the negotiation skills.
Before you act further It shall be appropriate to show the job advt, job application, interview call letter, offer letter, selection letter, appointment letter, CTC sheet, Salary Structure, Salary slips, STANDING ORDERS APPLICABLE TO THE ESTABLISHMENT (CERTIFIED/MODEL) AND EXTENDED TO YOUR DESIGNATION, HR policy, Service rules and regulations, Conduct and discipline rules, resignation letter/termination notice, etc …………. Communications exchanged with company to a competent and experienced Labor consultant/service lawyer at your location, give inputs in person and proceed under the expert advice of your lawyer.