My employee contract got expired ..this September...

You have to file a complaint at the labor office against this worker as she worked for a competing company which caused you serious damage and taking into consideration to ask for compensation for the damage you have suffered as a result of her action.

The Federal Labor Law stipulates that: 

Article 127:

Where the work assigned to a worker allows him to become acquainted with the employer's clients or to have access to his business secrets, the employer may require him to undertake not to compete with him or participate in any enterprise competing with his own, after the termination of his contract. For such an undertaking to be valid, the worker must be at least 21 Gregorian years of age at the time the agreement is concluded, and the agreement must be confined, in terms of time, place and the nature of the business, to the extent necessary to safeguard the employer's legitimate interests.

 It should be noted that after reviewing your inquiry and legal scrutiny we would like to inform you that you shall inquire through the Ministry of Human Resources and Emiratisation website

the Ministry of Human Resources and Emiratisation website