Fault is yours.
You on your own are not able to negotiate with your employer.
You may try by involving elders, influential citizens known to your family.
You may visit o/o labor commissioner/wages inspector and lodge your grievance.
This may give you negotiating arm.
In all probabilities you shall get work experience certificate based on attendance record, ID card mail id and emails exchanged with company. It is believed that so far your employer has not issued any email/ communication leveling any charge. If the employer gives negative feedback with vindictive approach to affect your employability, source of livelihood, you can also sue him.