asYou should first file a police complaint regarding your missing marks cards, they will give you a complaint copy. After that, you can apply for your duplicate copy.
Enclose the form, fees receipt, FIR, and affidavit in an envelope and send it to VTU. You can also visit VTU, by yourself.
Go to the VTU website and make payment for the duplicate marks sheet. Here are some of the things that you need to note.
You can send your documents through courier or visit VTU Belgaum directly. If you visit VTU directly, you will get your duplicate document immediately. Otherwise, you will need to wait for the currier.