Hey there

If you have paid extra amount during your payment you can write a letter to the account section or the director of the institute depending upon there policy so then you can easily get the refund of that amount. 

Feel free to ask questions

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/&ved=2ahUKEwil0L_Zm7fkAhUEXSsKHbcRBxIQFjAAegQIBxAD&usg=AOvVaw0kXTs63lu0AEzhiIz4mPU8

Good luck