Poor security measures

I decided to open an account on the app, obviously first thing first it wants my ID number but when I press next it says ID number is already registered but I've never opened an account...so I thought maybe "there could be a problem" it's not really registered but I try to log in with my ID number and pressed forgot pin, it did what other apps do which is sending a verification code via sms and it shows a cellphone number that I don't even know....