No, it depends when it became evident that the wrong item had been supplied (keeping in mind that acquiescence is an equitable defence and is available entirely at a court's discretion).
If it was clear before they were fitted that under-rated springs had been supplied then the purchaser could be said to have acquiesced.
If it was not clear that the wrong springs had been supplied until after they were fitted, then it is most likely a simple breach of contract. The supplier (assuming it is an Australian supplier) is then liable for damages for that breach. Damages would, in this case, be the freight costs at the very least.
Probably a letter of demand would suffice.

