On the "persoons" card in the City Archive of Amsterdam it says that Erna B. Blochert was sent to Germany on July 12, 1943. But at the same time the card informs that Erna died in Sobibor on July 2, 1943. Those two dates don't match.
According to the card Erna lived at the Watteaustraat 3 III. This implies that Erna was the housekeeper of Liesl and Werner Levie.
Liesl Levie shared some memories of Erna. She knew that Erna had a guesthouse ("Pension") in Germany, and had become a very dear friend of the family.