We checked with the internal team to get the monitor warranty updated. However, this request was denied as there is no Dell order number associated with the product. Please reach out to the retailer & ask for the Dell order number. Once we have these details, we can get the ownership transferred to your name & get the monitor replaced/ serviced as per warranty.    
I purchased a Dell E2016HV monitor from a local retailer two years ago. Now the monitor not working, when I called the dell service, they are asking for service tag. When I entered the service tag , the system says the service tag I entered is invalid. I am unable to contact the customer service executive to resolve this problem.
Invalid service tag