Sellers sometimes refuse to sell if an item didn't reach the price they wanted, but this seller has relisted the item for the same price which suggests that they may have relisted it by mistake.
They can't have cancelled the sale because you didn't pay. The auction only ended yesterday and sellers have to allow four days before cancelling for non-payment.
The best thing to do is to message them to ask about this? By the way, I take it you saw that the seller described the item as not working? This isn't allowed, as eBay requires items in "acceptable" condition to be still in usable condition. If you didn't realise this you could ask the seller to cancel your sale. It would be sensible for them to agree as if they refuse you could probably use eBay's money back guarantee to get a full refund. The seller would also have to send a prepaid return label if they want it back.