I've had a German collection come after me for 2 years with payment notices. I had unsubscribed by mail (which they got) and some email. They stopped last year

I've had a German collection come after me for 2 years with payment notices. I had unsubscribed by mail (which they got) and some email. They stopped last year after I wrote to them I considered I didn't own anything (a human probably read the file and dropped it).