I have received checks in Germany in the last decade, specifically when a health insurer refunded premiums but did not have bank details on file for me.
“Not a thing” is a confusing idiom. It specifically means never happens, ever, but the idiom is frequently used in contexts where hyperbole is expected, so a literal translation accounting for the hyperbole might be something more like “I’ve seen it once, but it’s vanishingly rare”.