XEM disappeared from IOS mobile wallet after Symbol was launched

I lost all my XEM in official NEM mobile app on IOS after Symbol was lanched. I mean It dissapeared from my wallet. I transfered this wallet to desktop wallet but there is the same, I have zero XEM in this account.
In fact at first it showed ‘Lost Connection’ and after I changed server now it shows zero ballance.

The problem was solved just restoring with private key. So the question how come my account was replaced with diferent address?