To you and anyone else who beleives the have a defective item. Buy the same item, make sure it is OEM, use a credit card. Then return the non working item for a refund. A cable does not have a serial number, and even if they did, it costs the company more to check them, and deal with refusal. Buy from a phone company if not the manufacturer. (dont do this to private small sellers, they dont have return agreements with manufacturers).
Note the reason using a credit card is important is if the merchant refuse you a refund (say they will only do an exchange) you can go to the CC company whos interest is to make sure you are not being charged for something that can be claimed defective.
The beauty of the item being OEM is the manufacturer will take the end hit, when the defective items are either credited or replaced. And if the large vendor takes a hit too often (defective item returns) they will avoid that manufacturer if possible.
This is better in for you in the near term because it effects the manufacturer, and gets you the item you need (and were promised). A class action wouldnt do much for you, it would hurt the company more, and help out (a) lawyer/s.
This is how as a consumer you can fight bad practices, and protect your interests. Companies dont want you to know about it, because it is near impossible (cost ineffective) to counter for low dollar items. Or crudely said, there are people that f**k and there are people that get f**ked.