Handling Career Challenges Due to Past Employment Issues
The small mistakes we make at earlier stages can affect our careers in later stages. Your story is one example. There have been several posts like this in this forum. Regardless of the company you work for, whether it is registered or not, when you are working and receiving a salary, you have to be formally and properly relieved, whether the notice period clause is mentioned in the appointment letter or not. You should submit a resignation letter stating "with immediate effect," "one month notice," or whatever you prefer. You must handle this in a bold and professional manner. Negotiations could have taken place back then, and you would have been properly relieved with a relieving order and service certificate. However, now you are in a different position, and the company's position is different. Ego comes into play. They are not obligated to do any favors for you now, as they view you as someone who was trained there and then left when you started generating revenue.
You mentioned that you submitted your resignation and they did not allow you to serve the notice period. Do you have any documents to prove this? Did you obtain your service certificate immediately when they did not allow you to serve the notice period?
If you do not have any of these documents, you need to go to their office, meet with them, and negotiate. If they request payment for the notice period, negotiate and settle it to obtain the service certificate. This is the best way for you to resolve this situation.
If they remain adamant even after negotiating with them at least three times and do not agree to settle, you can consider taking legal action.
Keep in mind that you may be able to persuade them to settle the issue without resorting to legal action, which can be a lengthy process.