May I presume that your query relates to the work-stoppage of your unit situated in India?
Forming an employees' union is a fundamental right in India. I think that the problem would have escalated to the level of strike by all the 21 employees in the establishment because of the indirect protest shown and the actions to scuttle the efforts against the union formation by the management. Agitation by employees en masse is a symptom of constant discontentment and formation of a trade union is a natural sequence and consequence as well.
You haven't mentioned under what circumstances the Government issued the letter to allow the striking employees resume work. Is it out of conciliatory talks conducted by any Labor Officer/ALC/DLC of the State Labor Dept or any Revenue Dept Official like Tahsildhar/Sub-Collector/ Dt Collector?
If it is an interim advice given by the Conciliation Officer appointed under the Industrial Disputes Act,1947 while the main issues are still pending conciliation before him, the employer can not punish any employee for any misconduct connected with the pending dispute by way of dismissal without the prior permission of the Conciliation Officer as per sec. 33(1)(b) or in respect of any misconduct not connected with the dispute, the employer has to seek the C.O's approval as per sec.33(2)(b) of the Act respectively.
That apart, the employer can not straight away dismiss an employee for the misconduct of abandonment of services without observing the due process of law like framing charges, conducting a domestic enquiry and the like. If he does so, the order of dismissal would be set aside in Judicial Review later as illegal resulting in reinstatement with back wages and continuity of service.
Therefore, tread cautiously and make amends accordingly in the interest of amicable industrial relations in the long run.
9th July 2018 From India, Salem