Holding Course Completion Certificate

I joined Full Stack Development Course in Jun 1 2023, i paid Rs.30,000 fees for it. In the acknowledgement paper they mentioned course duration is 4 months but they took class for 6 months, doesn't cover important and advanced topics as per they promised. After that they gave project titles to get the course completion certificate. Initially they asked me do Customer Relation Management System using frontend only. But I did that project in Full Stack includes (both frontend and backend) for adding much weightage to my resume. Now they are demanding to do full project they made keep on changing project by adding new titles and new features. I asked for the certificate because this project took more than 3 months and it is waste of time for me. They keep on pressuring me to do the project by adding new features. And they never mentioned me that they are going to use my project for their purpose. Finally when they agree to give the certificate still one feature inclusion was pending i never agreed to do that, at that time they put a condition for me we will provide the certificate but you have to give project support, but i denied that. Because I am not working for them i am just a student there. When we had a ugly fight during this issue, he used terms like i am not here to hear you, you are in the position where you have to hear me and do what i say. Your project is not worth and you can't show it in the interviews, because your code is unreadable (Note: they didn't teach me any advanced topics). Currently i am working on the last feature which is very complex to get my certificate. Including this in their advertisements they mentioned i you completed the course you will get the salary of 5lakhs to 10lakhs, but they offered me job with the salary of 10,000 (i said i want 20,000 as minimum salary) but he mentioned that with your minimum experience in this field you cannot get much salary. He totally shook my self confidence, disrespected my work and my self respect and doesn't value my time.