Hotel reservation details got leaked

I made an online reservation at a hotel in Amsterdam 3 weeks ago for an upcoming trip on the hotel's official booking site and also paid.

Last night I received a message on whatsapp from a phone number from Czechia saying my booking wasn't confirmed and I had less than 12 hours to do it by clicking on a link. It looked like a phishing attempt and scammy so I didn't click on anything. But the message had my full name, check in and check out dates and the fact that they even got my phone number.

I took screenshots and emailed the hotel, they replied that several guests received such messages and that we should block the number. However this was a bit alarming that someone was able to access my personal data that way.