Short answer. If the goods have not yet been delivered and the buyer has openly repudiated the contract, you as the seller may totally rescind it simply by giving the buyer notice of your election to do so — no court action is required first for this particular remedy to take effect.
What the law says
Where the goods have not been delivered to the buyer, and the buyer has repudiated the contract of sale, or has manifested his inability to perform his obligations thereunder, or has committed a breach thereof, the seller may totally rescind the contract of sale by giving notice of his election so to do to the buyer.
Civil Code, Article 1597 — Seller's Rescission for Buyer's Breach. Read the full provision →
When this remedy is available
This rule applies specifically where delivery has not yet happened. If you have already handed over the goods, this particular provision no longer fits your situation, because the point of the rule is to let a seller who still holds the goods walk away from a sale that the buyer has already shown will not be honored. It applies in three overlapping situations: the buyer has repudiated the contract outright, the buyer has shown an inability to perform, or the buyer has committed a breach.
Repudiation covers what you describe
A buyer who openly told you he will not honor the contract has repudiated it — this is the plainest form of the three grounds the law lists. You do not need to wait for the delivery date to pass or for a formal missed payment before acting; a clear statement that the buyer will not perform is itself enough to trigger your right to rescind under this provision.
How to exercise it: notice, not a lawsuit
The mechanism here is simple: you rescind by giving the buyer notice of your election to do so. The statute does not require you to first file a case in court to unwind the sale — the notice itself is the act that rescinds it. Because a dispute may later arise over whether notice was actually given and what it said, put your notice in writing and keep proof that the buyer received it, since that record is what will matter if the buyer challenges the rescission afterward.
What rescission does and does not settle
Rescinding the sale releases both sides from the obligation to go through with it — you are no longer bound to deliver, and the buyer is no longer bound to pay. It does not, by itself, resolve any separate claim you may have for losses caused by the buyer's repudiation; that is a distinct question from the rescission itself and depends on facts this provision does not cover, such as expenses you already incurred or a resale at a lower price.