Bad debts with vat & cst

Dear all,

                Just i want to know that we have some customer whose are not able to pay/ don't want to pay our outstanding payment for 4 years that's why we would like to convert in bad debts but can we get claim from sales tax department for payment of VAT on those goods because we had not received VAT amount from customer and we had made payment of VAT to sales tax department so kindly suggest me can we get claim for VAT amount ?

Ram Chandra Khichar