Odido swapped my phone number with some other random person

I was a KPN client and approximately one month ago I decided to switch to Odido while preserving my old KPN number.

Today the number transfer was supposed to happen. Unfortunately, Odido assigned me a wrong number and my KPN number was assigned to some other random Odido client!

Something went wrong on Odido's backend or it was a human error, but my old KPN number was assigned to some other guy and instead his number was assigned to me. My guess is that Odido (or KPN?) swapped our ICC numbers in their database. Accidentally, both of our Odido contracts have started today, and accidentally, we both are located in Delft. I don't know if it's a new contract for him or if he's also requested a number transfer.

What is more annoying, is that I was able to get access to his personal details, home address, his IBAN, through https://www.odido.nl/my/ when I added the new Odido number that I've got assigned today. I guess, he could access my personal details as well, by using my former KPN number. This is definitely not nice as if one of us would have bad intentions this would be a potential security threat. E.g., he could potentially get access to some of my messengers or approve transactions from the services that use one-time SMS passwords.

My old KPN SIM card has already stopped working, so at least in that KPN did their job correctly. I should also mention that the number that my Odido SIM card got assigned today is not the temporary number that is written on the Odido SIM card. I guess the same happened to the second guy who got my KPN number instead.

I've contacted the Odido client service by phone today, as soon as I could. I also informed the second guy, who has now my number, about the problem, and asked him to contact Odido as well. The Odido client service person said that this problem is new to him and I spent quite some time on hold waiting for a solution. Unfortunately, the client service was unable to instantly help me today and they said that they will call me back (to my work number, hehe) within 2-3 days! To be honest, from the safety perspective, I'd prefer that the both SIM cards would be blocked immediately and the new physical or eSIM cards would be issued with correctly assigned numbers.