Legal Question in Business Law in California

If I understand what you're asking about (the facts given are a bit sketchy), I'd say there is a technical breach of contract. However, bear in mind that breaches of contract are not all alike and not all have the same consequences. Some are "material" breaches that give rise to the possibility of a lawsuit, or may terminate the non-breaching party's duties. Others are not material and do not give rise to a cause of action for breach. In the situation described, the business has apparently made a mistake, has suffered most or all of the harm, and while it has not lived up to all of the terms of the contract, it is probably not going to lose any lawsuit brought against it for damages, for termination of the contract, or any other kind of relief.