BlackBerry Support Centre

I often complain about the SOS network operators on my BB , although before was full power aka 3G networks. Of course, my BlackBerry smartphone can not make to browsing, SMS, BBM, facebook, twitter’s, etc., will not do!  Because errors can occur on the network operator signal that suddenly disappeared. . I Cant  do anything. What are the things to watch out for?
I try this method   and give some way of solution below .

1. Please to Turn off   your BlackBerry, and do a hard reset. Then plug it back and wait a while if the SOS sign is still there or has changed to 3G.
2. If still no signal, please check Manage Connections and make sure the field is in the position of Mobile Network is checked. Then, do the reset registers in Host Routing Table to register your BlackBerry to the network operator you are using by going to the Options menu> Device> Advanced System Settings> Host Routing Table. Press the menu key and select Register Now. Make sure you receive a message that the registration.
3. If all of the above has been done and is still the SOS network, try to remember your sim card. Are you registered with the identity that suits you have. Based on experience, I had to register sim cards carelessly.  Checked other Blackberry wear too. I checked use normal mobile phone and a new understanding of what happened  that”My card was blocked” .
   If this happens, then you have to counter nearest operator to reactivate your sim card is blocked.