"they send it  "

They pretend to send it ....all lies!

"next day they say they could not deliver to my address and then refund me "

They're all  shonky sellers who are dropshipping.

They  cancel the transaction using  the reason that there's a problem  with the buyer's address when they're out of stock.

They'll be penalised by eBay if they use the correct reason.

Leave them all negative feedback and report them