Hello Harpal, welcome to the Community!
I see you've also opened a case with our customer advocates team in the support portal. Since Community is public, I'm unable to provide private details about your account or Cloud site here. The customer advocates will respond on your support case.
In general, it's worth reaching out to your company's IT department. If you are leaving the company, they should have a process in place for closing your accounts. If there is some other consideration, your IT / Jira administrator will be in the best position to take action. If you don't know who this person is, it's worth asking your manager or human resources contact to get in touch with the Atlassian Cloud admin.
Daniel | Atlassian Support
Hi @Rosa Clark ,
The best thing to do is contact your organization's IT department. We can't share details about specific sites on Community. If the IT department doesn't specifically own administration of an Atlassian Cloud site, they can usually follow up with a finance contact to locate the administrator.