Do I have to serve my notice period after completing my rotational leave?

Good afternoon.

I have been working with my employer for the past 3 years and 9 months. According to my contract, I am required to work 42 days and take 21 days of unpaid rotational leave.

6 months ago, my employer changed my rotational working cycle to 60 days of work and 60 days of unpaid leave. I did not agree to this change, but I have been working under this new cycle for the past 3 rotations.

I resigned from my job while I was on rotational leave and requested to be released from my contract with a 30-day notice period.

However, my employer informed me that I must first complete my rotational leave, which is 60 days, and then serve a 30-day notice period after returning to work.

I have another job that I need to start in 20 days, but my current employer is not releasing me. I officially submitted my resignation via email on July 12, 2023, from India.

Due to this issue, I traveled to Abu Dhabi on July 18, 2023.

Please advise me if I must serve my notice period after completing my 60-day rotational leave, or if it can be calculated from the date of my resignation.