Hi,
As per your private message to me ("Actually I had resigned due to my personal emergency, hence can't serve a 30-day notice period. I resigned via email and also on the online portal, and I'm not currently on the company's payroll. However, I have not received any response to my email or on the portal."), in my opinion, if you are not being properly relieved, your current employer may not provide you with proof of employment such as an experience cum relieving letter. This may be required when you apply for a new job in the future.
Please let me know if you need further assistance.
Thank you.