When you buy from a shop and the product fails within a year you get a replacement or refund. How are guarantees upheld if not its makes ebay a mine field and we had better purchase thru Amazon. the company is UKnewpower
Buying from an online seller isn't the same as buying from a large retail outlet that offers a 12 month guarantee.
Any guarantee is only ever going to be as good as your ability to enforce it when required. If your seller (who is based in China) offered a 12 month guarantee with the product then this is something you really should've considered at the time.