Company Forced Notice - can they change terms in between of Notice period (company initiated)?

Hi, Our company had put many on Company initiated Notice in June start, with 90 Day notice period with a designed Severance Package. At time of announcement from MD, he mentioned that if employee seek early release they would be allowed so as career would be impacted bla bla.
Now, one month later when few asked for early release withing 2-3 weeks based on case basis... they have sent email Quoting Reference from offer letter about Buy out Clause, and employee needs to pay to Company.
I know these days Spitting and Licking it is in Fashion, and there is no value of words.
First, Are they allowed to do so? If they didn't mention it earlier than can they change terms in between of Notice period (company initiated)?
What action can be taken against the Employer?

Can someone Post/provide their views on this ?

Sagin - Such cases are at its peak these days - where learned Corporates even just display lack of empathy and cooperation and are resorting to such extreme measures. Here, you just have to focus on the factors that you can control.
Practical advice:
1. Termination/ lay-off is illegal during the lock-down period. Please speak/ write to your local Labour Union citing the details of the case, and an action may be expected then.
2. If you have accepted severance package via e-mail/ letter/ HR portal - then you are bound to oblige. Corporates will always make it a 'make-or-bend' situation for them - and will go to any extent to accomplish this.
3. Corporates reserve the right to alter any clause of your offer letter - it is generally missed being read by employees but it is always there. In your case, they would do it - so that they can recover some valuable money from employees.
Action: Please serve your notice period, avail severance pay package and come out clean. All your dues should be processed as a part of your FNF. Also, insist on a relieving letter, as soon as possible and search for a job aggressively. Going the legal way is not recommended as it is a cumbersome, costly and lengthy process, unless you have time and good finances to fight your plea in a competent court of law.
Don't worry - losing a job is not an end of the World and you may hope for better times ahead.

Read this for termination or forced resignation https://www.citehr.com/620431-employ...ny-during.html