Notice period extension without communication over email

I work in a company in Mumbai. As per my appointment letter, notice period is 60 days. After my joining, the Company increased its notice period from 60 days to 90 days last year. The Company increased notice period through a memo that was circulated over email. I never received the email, they forgot it to send to me, specifically. Later on they uploaded the memo in policy section of Human Capital Management portal. I never went to the portal and read the memo, and hence was not aware of the memo until I resigned. Also my appointment letter has below clause: "All Terms and conditions will be governed by the Company’s policies as stated from time to time and the Company may in its sole discretion as it deems fit revoke or change such policies. It shall be your duty to peruse and understand all the terms and conditions enumerated in Company’s Policy as well as the repercussions of the breach thereof and not being aware of the same shall not be a defense, which shall be either available to you or accepted by the Company." Considering above, am I obligated to serve 90 days notice period? Was company not at fault as they did send notice period extension memo to every employee except me? Please tell me reasoning that I can give quoting any law.