20 January 2013
The very first step is read dvat law and find the way / procedure to make any change / correction in the challan. If the Authority empowered by the corresponding law for making such amendment then any possibility remain to move the payment from VAT to CST. Otherwise CST is to be paid and the wrong payment can be asked for refund.
26 July 2013
If you have made the local sales then yes VAT has correctly been paid and in case you have made the inter state sales then you have to pay CST. If you have wrongly made VAT payment then against your VAT liability you have to adjust and in addition you have to make the payment of CST