I am not sure you are fully ready to be trying to sell on ebay.
How could you not know that someone had purchased your item? It would show up in your account section, surely. You need to check this regularly when you have items listed for sale.
A buyer does not need to communicate with you before buying, not if they are buying at the full advertised price. They can just hit the Buy tab and pay without any communication with you whatsoever. That's how I usually buy.
Obviously, if someone makes an offer, you may get a message but even that is not certain as some sellers have their acceptance prices pre set for that too, so it is all automated.
Your main problem is it does not sound as if you are signed up to managed payments. If you want to sell on ebay, you have no choice, you need to sign up for this. Ebay will need your account details if you are ever to receive any money. How else could they transfer it?
And another thing: New sellers or occasional sellers, even when signed up for managed payments, have a 30 day hold on their money. It's a security thing. Once that 30 day hold has passed, then the money is released.
But in the meantime, you as seller would need to send your sold item asap, regardless of not having actually received the money for it. Once you become a regular seller, that 30 day hold disappears.
If someone made an offer, had it rejected but then bought at full price, I doubt it is a scam.
Unless you sort out managed payments though, you will never get the money. The buyer may have paid though and will probably go through ebay to ask for a refund when their item is overdue. Your selling account with ebay will be in trouble if you keep selling things but never sending them or checking on what has sold.
You need to read through the help pages thoroughly before you attempt to sell anything else.
