Update = Resolved After completing troubleshooting, a DELL-Cares agent setup a monitor exchange.
I have been using Dell 24 LED HDMI Monitor on my desktop since last 18 months. It showed display issues from December 2021 and I contacted Dell customer care on 6th January 2022, and as desired by the technical team I emailed the documents like original purchase bill and images of the monitor as specified by the team and did trouble shooting methods. Finally I received an email from the technical team stating that my monitor would be replaced and later another mail on status update on Dell dispatch. I tried to contact the Dell customer care toll free number and was unsuccessful. After few days, I received another mail stating that the part to be replaced is on the back log and have to wait. Then after few days again an email repeating the same was received (21st January 2022). I would be helpful if anyone could explain to me how much time should a customer wait normally for getting this kind of issue to be solved. Update-Resolved- I have installed the monitor (U2422H) received under warranty yesterday. Its working perfectly. 
Monitor exchange, backlog