Have Exp Certificate But No Other Proof Of Employment

Hi,
I am quite a new member here. I had worked in past for 8 months as a freelancer. Just to make sure that it should not be shown as a gap in my employment (as it was not registered organization type of and just group of 5 people) , I was provided with a formal experience certificate mentioning date of joining and relieving over it. Now I have got selected in one company, where I have submitted this document. Currently that company is no more in operations (it was a freelancing group operating 4 years back). Kindly suggest me how to deal with this issue as current employer needs an evidence for that particular employment and I don't have anything with me now.
Kindly suggest me how to deal with this.
Thanks

Too many gaps...
In past you worked for a company as freelancer
Duration - 8 months
The company is closed down.
4 years back it was a freelancing group...
I am sure in this 4 year's time you must have worked somewhere.... can you elaborate

Yes, I joined another company and I am currently associated with them only. And now I am switching to new organization.

So how did you show your experience to your current firm?
You mention you have experience letter from your freelancing firm.... if it mentions the tenure it should suffice.
Your recent experience is more important.
What is the trouble please elaborate.

Current organization has no issues with it. New organization is having as they are doing background verification and not able to trace through that particular experience. Hence they are asking for more proofs.

Hmm...
You should be honest with them and say it was a freelancing firm, and you worked with them for 8 months so that there is not gap in your employment.
Apart if your current organization can help you with it by giving their experience on you and how they verified you then about the work experience with this freelancing firm...
I think there is no other way but to try to convince the employer and show the truth...
All the best

You must be in touch or have contact details of the owners of the company you used to work with 4 years back. With approval of the owner, share his phone number / email I'd with hr and let them speak and get confirmation.
It's no crime to have worked with a company that has since closed (assuming you we're not responsible for closure) and hr understands that.