Hello! Obviously, if you are not sharing any details to the scammers, there is nothing they can collect. Maybe, they can figure out your cell operator or region, though I doubt this has any value for crooks. The only possible way they can still mischief you, as far as I see, is putting your phone to the list of “active”; then a list of numbers of people who called them is sold to other crooks. Numbers may then be targeted by scam SMS (like fake USPS delivery notifs) or scam calls. That’s it.