Blocked from getting a phone contract – no explanation given

Hi all,

I’ve been living in Switzerland for 5 years and moved to Zurich about a year ago from another canton.

I’ve always paid my bills on time and never had any issues, but today a cellular provider refused to give me a long-term contract, saying I’m “blocked for credit.” They couldn’t tell me why due to privacy reasons but told me to contact the authorities for further information.

Has anyone experienced this? I’m confused since I don’t think I have any unpaid bills or past problems. Where should I check, and what could be causing this?

Thanks in advance.