Promotion in Govt. Service (Autonomous body)

My claim is for promotion to the post of Section Officer from the date of my application 27/6/2019. Last year around the month of May 2019, an employee, who was working in the capacity of Section Officer (Ad hoc promotion basis) refused to continue carrying duties citing health and other issues and was allowed to relieve from duties as SO, thus creating a vacant SO post. On 27/6/2019, I filed an request in the office for promotion to the post of Section Officer. As per Recruitment Rules, i completed the eligibility of 8 years regular service as Assistant to be eligible for promotion. There is no one else in the feeder cadre eligible who may claim the post. But, even after 1 year of my request no decision has been taken or communicated to me. It is to be noted that I was on deputation to other govt office as on 27/6/2019 and reverted back only on 01/6/2020. But, I believe I could have been given proforma promotion as per DOPT rules and on reversion i could have joined as SO.