Is It Legal for My Employer to Extend My Notice Period Without Formal Notice? What Should I Do?

I was given an offer letter in May 2020 with a 2-month notice period. Now, I have an opportunity where I need to join after 1.5 months, so I am willing to pay for the remaining 15 days. However, the management is claiming they sent out an email on March 1, 2021, which extended my notice period from 2 to 3 months. Is this even legal? They have not provided any formal notification or updated document. What steps should I take next?

Management's Rule Enforcement

The management can enforce any new rule only after informing the employees, particularly when it involves amending the contract of service. You must respond by stating that, as per the contract of service you entered into, the notice period is only 2 months, and there cannot be any unilateral changes to it.

Addressing the Email Dated 1st March

Regarding the so-called mail dated 1st March, emphasize that it is an afterthought, a backdated document that has not been communicated to you thus far. Since the amended clause is detrimental to your interests, it can only have a prospective effect. This means that it will apply to resignations made after the communication is issued, unless an alternative effective date is specified.