Hello Aspirant,

Colleges are not allowed to withhold your certificates for any reason. Since this is a case of you leaving the medical seat in the middle , the amount you will have to pay depends on the college admission and exit policy. If they are demanding unnecessary fee or complicating the issue you may even proceed legally , however you may have to pay the fee based you the period of the course you attended ,this is because when you leave a seat in the middle there is a vacancy created and the college will be at money loss . But again remember they have no legal right to hold your certificates because The University Grants Commission (UGC) has issued a warning to universities and colleges against the retention of original documents of  students.You may seek help from the appropriate court.

All the best