The state has prepared the seniority list on the basis of direction of the high court. But there is a serious error while passing the promotion order. The promotion should have been on the basis of merit cum seniority.
But in your case the promotion was done on the basis of seniority only. This is against the rule. Therefore, you should immediately challenge the promotion order. No need to challenge the seniority list because it is prima facie correct.
As per the merit cum seniority rule the meritorious candidate should be promoted however he is junior in the seniority list. Your seniority is lowered three steps but as per the facts of your case you are more meritorious than the senior.
Hence you should move a writ petition in the high court under article 226 of the constitution of India. You should adduce evidence that the promotion was done on the basis of seniority only however, according to the prevailing rule the promotion should have been done on the merit cum seniority basis.
This promotion order is violative of article 14 and 16 of the constitution of India. Therefore, the high court may quash this order.