Incommunicado Once the Deal is Done

I ordered online a quantity of electric wire. The order was handled most efficiently and delivered a day earlier than forecast. Excellent! However it was immediately apparent that, while the product label agreed with that which was ordered, the product in the package didn't match the label - it was a higher grade of wire that costs more than twice the price I paid. Someone had mislabeled the cable and the mistake could only be expensive for a seller somewhere up the line. I immediately emailed Stemar with the suggestion that they check whether they weren't selling their stock at a loss. I also offered to return what they'd sent me, the packs being pristine and unopened. I waited in vain for any response. A few days later, thinking they might not understand what I'd previously reported, I sent the manufacturers specification for the cable sent versus the cable ordered. With documentary proof. The cable they sent contained more than twice the copper that I'd paid for. No response whatsoever. If this is how they treat a client that's trying to help them, imagine the impenetrable wall of silence if you'd ever want something FROM them. Better to play it safe and buy elsewhere.