The demand of fees depends on the policy of the college. If the college policy states that on leaving college in the middle, remaining fees is to be paid then you will have to pay the whole amount. Meanwhile if you do not have financial resources and despite asking the college if they are not considereing then you may file a writ petition before the High Court.
Also, if the college is not returning the documents until you pay the fees then you may file a complaint against the college.
The University cannot withhold your original documents and papers. The University Grants Commission (UGC) laid down regulations for universities and colleges against the retention of original documents of admitted students and non-refund of fees in case an admission is withdrawn within one month.
It also laid down that students must not be compelled to submit their original personal certificates like marksheets, school leaving certificates, etc at the time of admission form submission. Original can be collected for verification of attested copies in the presence of student at the time of admission after which it should be returned. The institutions cannot take the originals into custody.
In the present case, most private colleges demand fees for the remaining years if you quit midway. If your college is a private college then no legal action can be taken regarding this matter.
Reference: Constitution of India