One entry, not two
A standalone khata app is a digital version of the register and still needs every bill typed twice — once for the customer and once for the app. The moment somebody is busy, the two stop matching. Here the bill is the ledger entry. A credit sale updates the party's account as it is saved, a payment closes it off against specific invoices, and a return adjusts both. Nothing is entered twice, so nothing drifts, and there is no month where you have to work out which of two records is right.
Ageing is the number that matters
Knowing a contractor owes four lakh tells you very little. Knowing three lakh of it has been outstanding past ninety days tells you to stop supplying and start calling. The outstanding screen ranks every party by amount and by age, so the morning call list is ordered by risk rather than by whoever came to mind. Age predicts whether money comes back far better than size does, and it is the figure a paper register can never produce on demand.
Credit limits, before the material leaves
A limit set against a party produces a warning at billing time when a new bill would take them over it — while you still have the leverage, rather than afterwards when you do not. It also gives counter staff a straight answer to give a regular customer without having to make the decision themselves, which keeps an awkward conversation away from the counter and with you. Most shops set limits only after being burned once; the ones that set them early rarely are.
Let the customer see it
Most credit disputes are not dishonesty, they are two people with two records. The customer portal gives each party a login to see their own bills, deliveries, payments and balance whenever they want. Once a contractor can check his own account, the monthly argument about what was delivered and what was paid largely disappears — and when it does come up, both of you are looking at the same screen instead of at two different pieces of paper.