Notice period serve

I have joined a company to do internship for 6 month from 1st September 2023. As per offer letter I had to serve minimum 6 month internship. After 6 month no one from company sent me that I had completed internship or not. but I continued. No salary slip. No PF ESI. Only I got stipend every month. In April I got stipend / salary slip. But from May month again no stipend / salary slip. June month stipend till now I have not received. 16th July I sent resignation letter with immediate effect. 17th July 2023 they have marked me absconding. I did not serve notice period. As per my offer letter there it was not mentioned about notice period. Even in my offer letter it was mentioned that after 10th of the month stipend will be given. But from June not getting so. They told in mid July performance was not good so stipend will be on hold. We 6 employees from sales, All our stipend was on hold due to performance issue and in offer letter / verbally there was no prior information that due to performance issue stipend can be on hold. Now what to do? They are marking me absconding as i did nt serve notice period. but in my offer letter there is no mention about notice period and I didnt get any letter / verbal information that I have completed internship / permanent employee. What to do now?