Related to : SMS messages just have "null"

Try this,

delete their contact

then

Settings > Applications > Manage Applications > Select the Messaging App

Choose 'Clear Data' and also 'Clear Cache'.

N.B. you will lose all data / txt msg's in your phone

(don't forget to write their number down to save as new afterwards!)

You probably used 'getMessageBody()' to get a message text. But that's for the text sms. For data sms, you will need to use 'getUserData() instead, to get a message body. The code should be something like this

Bundle bundle = intent.getExtras();        
SmsMessage[] msgs = null;
if (bundle != null)
{
    Object[] pdus = (Object[]) bundle.get("pdus");
    msgs = new SmsMessage[pdus.length];            
    for (int i=0; i<msgs.length; i++){
        msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);                
        byte[] userData = msgs[i].getUserData();
    }

}