Sim Toolkit - "...Missing SMS Part..."

Hello, I’m using the SIM Toolkit feature of my BR1 running 6.3.3s095 build 2455

When I receive messages from my ISP, they are often truncated with the following words appearing at the bottom of the message:

…Missing SMS Part…

Can you tell me why I’m not able to read the entire SMS message? I’m trying to determine my bandwidth allowance, but this info is not displayed because of the above error. This requires me to remove my SIM and insert in a mobile phone to determine balance.

Thanks for your help.