Forceful extension of the employee notice period upon resignation

Hi Madam,

Good afternoon.

I am writing on behalf of my wife. She is working as a school nurse in Dubai for more than 3 years.

Now, my wife got a good offer and submitted resignation on 26th August 2018 by mentioning last day of working as of 07th October 2018.

The school accepted the resignation and asked for 45 days salary as compensation. We also agreed to give the compensation and informed the new school that she will join on 08th October 2018.

But now they are asking to work for some more days as KHDA inspection is coming to school by the end of October.

We told them it is not possible because we already informed the new school about the join date. The current school still have not started any relieving process.

How can we overcome this issue?