ICICI Prudential Life Insurance — Asking for money after my registration

I had joined ICICI prudential as an unit manager business development on 1 of September 2021 and only after 2 day I quit and informed the same to the HR. I had only received an offer letter and no appointment letter was given to me in the time of joining. Now after 2 months they had called me and asking me to pay an amount (which is even more than my salary) to release me as I have not served any notice period. As of my knowledge I have not received any such information and terms and conditions mentioning about the notice period.