I sent a letter to Jardin de San Federico, 13 and it has come back to me as unknown

I have written a letter to;
Loles Leon
C / o Carlos Ochandos
Pza. Vasquez de Mella, 2
28004 Madrid
and the letter has been returned by post as unknown ...

Frana Perea
A6 Cinema
C Talent Agency
Conde Xiquena, 13 3ª dcha
28004-Madrid

I sent a letter to this address and the post office returned it to me a few days later

Thanks