Navigating Background Verification Challenges with Previous Employers at Accenture

Hi, I am facing a critical situation and I don't know how to get out of this mess. Things happened - I worked in a company in 2011 that was very small (hardly 10 to 14 people). The company closed in 2012. Currently, I have received an offer from Accenture, which I have accepted. However, I could not onboard because they say background verification is pending for that previous company. I have provided all possible details such as the offer letter, relieving letter, and salary certificate from that company. Since the company has closed down, none of their landline numbers are working, and neither is their email. What should I do now?

After that company, I joined another IT firm, and it's been almost 2 years since I have been working here. I recently accepted an offer from Accenture, but the background verification is stuck at my past company. Do they verify and approve it because that company was there for sure, no doubt. I wonder and am a little scared whether they will approve it or not. Please help.