lost iphone / fake calls and messages from apple ???

lost my iPhone X ! I no longer see it on the map because its offline.... I've been getting text messages saying that it was found and redirects me to a webpage where I have to sign in on my apple account, which I didn't.... im in argentina, but I've been also getting calls from different Americans numbers, saying they were from apple support... is this actually real? how can I corroborate that the phone numbers are really from apple itself? ...