Hello sir,I was terminated from my services...

Since your visa expires in October 2021, but you have finished your work, in this case your residence will be canceled and you must leave immediately after the end of your stay, and you can also file a complaint against the employer before the competent labor department to demand an end of service bonus and a NOC issued by the employer
This is according to the provisions of the following residency law:
Article (28): Every foreigner must leave the Sultanate with his companions upon the end of his stay unless he had previously obtained a renewal of this residence
Article 33: If the working relationship ends, he shall pay the worker his wages and all the amounts due to him immediately unless the worker has left the work of his own accord, then in this case the employer must pay the worker's wage and all his dues within seven days from the date of leaving the work.

You can ask the employer until the end of your last day, knowing that you have to leave the country when your visa is canceled and you can appoint a lawyer to initiate the procedures instead of you in your claim for your dues from the employer, and you can also obtain another sponsor and transfer your guarantee to him instead of your sponsor who ended your work with him