Pending provision period closing due to cast verification

I am working in Department of Space in Thiruvananthapuram as as assistant and I got appointment in a post reserved for Scheduled Cast. I belong to schedule cast (Namasudra sub cast). At the time of Document verification in 2018 I produced my original certificate (issued on 2009) issued by Subdivisional officer of my area, I.e West Bengal . Now as per the instructions given through appointment letter dated 26 /11/2020 I had to again obtain a certificate in the format given in the appointment letter ( same format as my original cast certificate, i.e in line with MoSJ& Empowerment OM dated 10/08/1994). How ever I have obtain the same from SDO office in 2020 and submit at the time of my joining. Now when from my office they are sending for verifying the cast certificate issued on 2020, DM office is only stating that 2009 certificate issued verified but my office is only insisting on 2020 cast certificate. Now when ever I am approaching to DM office they are telling we in West Bengal only issuing life time cast certificate. And my 2009 certificate issued also available online. Now it's going for 3 years still my probation is not closed due to this. Is there any solution for this?