Money first , then they sign a contract.
Short: They asked the deposit before the contract was signed by both parties. Some details rose concerns about reliability of the company. Deal never completed. Multiple people answering the emails
More details:
After viewing the apartment, I was given a form to fill with my details. I did that but I found quite strange that the account they use was a gmail account instead a corporate account. I decided to move ahead. After that, they asked for many of my personal details and later on I was offered a contact (not signed) and I was asked,by email, to: deposit around 5k CHF in advance , sign the contract and send it by email. They would have signed the contract only after receiving the money and my signature.
"Wir bitten Sie, uns beide Mietverträge, sowie beide Unterschriftsformulare rasch möglichst unterschrieben zu retournieren. Sobald wir von der Bank die Bestätigung über die Bezahlung der Mieterkaution erhalten haben oder uns eine Kopie des Empfangsscheines vorliegt, werden wir Ihnen, das von uns gegengezeichnete Vertragsdoppel zukommen lassen und mit Ihnen einen Termin für die Schlüsselübergabe vereinbaren."
As I found such practice of an half signed contract a bit suspicious, I went to the address indicated in their form, but besides a mail box I could not find an office open to the public nor a doorbell.
I tried to access their website. It was not working (I am an IT engineer, so I know how to check such things)
Being a bit disappointed I informed them via email and they provided the below explanation....but to be honest I could not manage to restore my faith in the process:
"Was unsere Website betrifft, so hat diese bis vor kurzem ohne Probleme funktioniert. Wir danken Ihnen für Ihren Hinweis und werden uns darum kümmern.
Bezüglich der Kaution können wir Ihnen gerne ein Formular der ZKB zusenden, wo Sie ein Sperrkonto für die Mietkaution eröffnen können."..."Wir geben Ihnen gerne noch bis heute Abend Zeit, sich endgültig zu entscheiden, ob Sie die Wohnung mieten wollen. Ansonsten haben wir viele andere Interessenten für diese Wohnung."
Why would you want me to sign the contract and taking risks before having the agreement countersigned? Quite frustrating. I decided to give up despite the time spent.
As you can see from their message they have many candidates so they don't care about such details.
The only positive thing is the communication: via email and via phone they are responsive and they tried to accommodate my requests.