Hallo @lemekhov ,

welcome to the o2 Community .

That you can’t access mein o2 anymore at this point is normal. You get the full access only after the connection itself has been activated and a phone number is assigned to you, as the registration works with that number.
Do you still recall anything about the call that you’ve received, it’s nothing out of the ordinary that you do get a call beforehand, but that they explicitly called out that you’d receive a second one is interesting.

Kind regards, Sven

Unfortunately, I could understand very little German, and the operator didn't speak English well either. When I realized that I would be called again by someone else, the conversation finished.

I tried checking my order status at an offline o2 store, but the lady in there told me they couldn't see online orders. 

Hello @lemekhov ,

do you have someone that could help you with a call and translate the conversation when necessary for you? Because then you should definitely give the hotline a call and ask to be connected to the activation department.

Kind regards, Sven

I might have some help with translation only next week, that's why I tried to get help here. 

The support number I should call is 089787979409, right? 

Hello @lemekhov, 

the number you mentioned is the number for the order hotline. You can reach our German customer hotline at the following number: 089 78 79 79 40 0

And our English hotline at this number: 089 66 66 30 08 1

Best regards
Cora