re: "Help my account has been suspended. What could be the issue?"
Regular Forum participants are just other freelancers like yourself or clients. We don't know why you were suspended.
But: Upwork does not intend to simply suspend people without telling them either a reason why, or what they can do next, or both.
You should have been sent an email message telling you what you can do.
AND you can click on the "bell" icon in the top right corner of your Upwork web page to see recent notifications, wherein you should find information.
AND you can click on the "question mark" icon in the top right corner of your Upwork web page to go the the "Help and Support" page, which may have an open ticket for you, which you can find by clicking on "My Requests."
It appears your account was suspended a few years ago. I'll ask the team to follow up with you directly about your account status and provide available information.