Hello Sachin
Your situation reminds me of a similar situation for one of my processes.
Following are some of the actions that helped us stabilize the process
1. Daily team huddles (not more than 10 minutes) on the top error category. This team huddle has to be a quick one with a specific focus on only 1 error category. Discuss why such errors are coming and CAPA plans
2. Calibration of teams - client vs QC, within QC team
3. Clear progress roadmap for quality score improvement (we created a six month plan) in discussion with the client and leadership team
4. Agreement on a cool off period for errors due to frequent client changes (we agreed on a 3 month cooling period). However, this increases the task of QC team as they have to maintain a log of all changes and track errors against them
5. Make leaders process some transactions so that they understand the ground reality and once they understand, they will be able to guide the raters
6. For a 3 month period (and as a stop gap arrangement), we did overstaffing for QC so that things can be regularly checked. This was audit of audit (only recommended as a stop gap arrangement but never a long term solution)
7. Started working with the IT / automation team to see if there could be some mistake proofing opportunities within the software.
8. Availability of SME / Trainer on the floor to handle queries / doubts immediately.
Hope this helps.
Regards
Mayank Gupta