I have to solve one problem, example: we are one sale bill in tally for Rs 1500+14.50% vat thus together comes to say 2000/- after one day customer come and exchange the watch and buy new for 3000+14.50% tax say Rs 3500/- and he will pay us balance amount of rs 1500/- for this how we can make sales bill in tally for rs 2000/ credit and balance for adjustment bill kindly brief me