Gmac Financial Services — I have not received my NOC from the company after closing my car loan

I have not received any NOC from GMAC which financed my car loan for Verna in 2018. The loan was closed 2010 and the company doesn’t seem to be existing now. I have tried multiple ways to reach out them but failed to do so. I require your help in resolving the issue because I want to transfer my RC now. I can send more details regarding the loan.