Try to keep messages under the SMS size limit. Here's a link about that limit.
Sorry but anything over that is not SMS and as BB users know the end is nigh I can only nod and write I expected this.
I have a blackberry curve 9310 with straight talk. I can no longer send long text messages it will show as sent but the recievers will not receive. I have tried with multiple people with different carriers and same result. When I first got the phone I would be able to do this and it would just automatically send the multiple messages. I changed nothing with ther service and I don't know why I am no longer able to do this. Any advice?