Refusal to take responsibility for Non-Compliant installation

A gas geyser was installed at my home. Later, another gas installation was done by another party, however, he could not sign-off the new installation, as the installation by The Plumbing Lady / The Gas Lady was found non-compliant with regulations. It cost me R1 888 to get The Gas Lady installation compliant. I asked the Gas Lady manager to refund me for this. He refused, arguing that it would not be worth my while to take this to court, as the amount is too small. He may be right, but at least I can warn other unsuspecting customers.