Citizenship

Hi everyone, I am new here. I just have some concerns about my Interviewed last week. I just passed my citizenship test last week everything was fine. After the interview she handled me this paper saying:
A)you passed the tests of English .....

B) A decision cannot yet be made about your application.

I asked the IO, about the decision cannot be made and she told me that everything is OK just wait for the letter to arrive within 30-190 days. I remember when the time she called my name she said that she was just there to do the interview and it will only take 15 minutes, then that's it. After the basic questions about the history she gave me the paper to sign for changing name since, I told her that I want to change my last name.

I really feel disappointed. Is there any number that I can contact them to know if there is something wrong about my application or if they need some documentations from me?

Please help me out if know anything about this kind of situation.

Anyway, my status online is still the same, saying that they sent me a letter about my interview. Nothing has changed.

Thank you.