urgent

form H is meant for export goods, and while filling form H there are several columns which are related to shipment documents, so one cant issue form H errorneously in place of form C, coz the requisite data of export is missing, i.e onward transfer of goods to frontiers. 

if the same is used willingly then its offence and case may be booked as evasion of revenue and fraudent misuse of exemption forms.

of C form is used in place of H, i e. export is made after obtaining goods after C form purchase, then nothing have to do, its just loss of CST paid by the buyer on export items purchase.