A Call from Vodafone?

Hello,

I received a call from +49 800 7733134. The caller said he was from Vodafone and wanted to change my tariff. He knew my name and that I have Vodafone home internet. He also asked for personal details, such as my customer number.

Is this number legitimate? I wasn’t able to talk because I was at university, but I’d like to know whether it’s really Vodafone or a scam.

Thank you for your help!