Short answer. An unpaid debt on its own is a civil matter, not estafa. The Revised Penal Code punishes defrauding another, so there must be deceit or abuse of confidence — something more than a borrower who simply could not pay. The Constitution forbids imprisonment for debt.
What the law says
Any person who shall defraud another by any of the means mentioned hereinbelow shall be punished by
Revised Penal Code, Article 315 — Swindling (Estafa). Read the full provision →
The missing ingredient is deceit, not non-payment
The word the whole article turns on is defraud. A person who borrows money in good faith, intends to repay, and then cannot because his business failed or he lost his job has broken a contract, not committed a crime. The remedy against him is a collection suit. Estafa requires something extra: either a false pretence or fraudulent act done before or at the same time as the transaction — a fictitious name, a pretended business, a claimed property or credit the person never had — or unfaithfulness and abuse of confidence, such as misappropriating money or goods received in trust, on commission, for administration, or under a duty to deliver or return them.
Deceit has to come first
Timing decides many of these complaints. The deceit must have induced the other party to part with his money or property. If the lie came afterwards — the debtor avoided calls, gave excuses, moved house — that is bad behaviour, but it did not cause the loss and it does not convert the debt into estafa. This is why "he refuses to pay and now hides from me" is not, by itself, a criminal case. It is also why misappropriation cases turn on the character of the receipt: money received as a loan becomes the borrower's own, while money received to be delivered to a third person or accounted for never does.
Bouncing cheques and the notice requirement
The article separately covers postdating a cheque, or issuing one in payment of an obligation, when the drawer had no funds or insufficient funds. Even here the law builds in a chance to make good: failure to deposit the amount needed to cover the cheque within three days of notice from the bank, payee or holder that it was dishonoured is only prima facie evidence of deceit. That presumption can be met. A cheque issued as security for a pre-existing loan, rather than in payment, is treated differently from one issued to obtain something at the moment of the transaction, and the special bouncing-cheques law operates alongside this provision.
The amounts are the 2017 figures, not the old ones
The penalty brackets in the text above are those set by Republic Act No. 10951 (2017), which raised the peso values throughout the Revised Penal Code. Current thresholds run from ₱40,000 at the bottom to ₱1,200,000, ₱2,400,000 and ₱4,400,000 in the higher brackets. Many websites, textbooks and reference copies still print the 1930 amounts, where the same brackets read ₱200, ₱6,000, ₱12,000 and ₱22,000 — those figures are obsolete and will give you a wildly wrong idea of your exposure. Check which version any source is showing you. Because the line between a civil debt and estafa is narrow and fact-specific, have the documents reviewed with counsel before filing or answering a complaint.