IPhone 4: Blank text messages, dropped calls, slow Internet connection

i am having the exact same problem with the service and also with the texts, and not only that also sometimes people tell me that they receive weird characters in my text like " @$%^&#*()! " the worst thing is that i got the iphone probably like 4 days ago and ive been using it with a case all the time, im gonna have to go to an apple store and get it either replaced or fixed, if this problem persists i will cancel my contract with at&t

I have the same problem. When i send a text message the time the other party that is receiving the text says it is blank message.
and i noticed it usually happens with long text messages.

Has anyone found a solution?

I, too, am having this same problem. Text messages to my friend on Sprint sporadically arrive blank. I checked to see if there were any special characters, but there were none. It all seemed to start after I sent my first MMS with a pic.

A search for "blank text message" on here only brings up this thread. Hard to believe the problem is this isolated.

Change setting of Keyboard back to English only...It works for me

I just bought a couple of iphone 4's last week (one for my wife and one for me). After two days of using it, my wife commented that her sister (who lives in Los Angeles, we live in Seattle) was receiving "some" messages blank. Originally I thought it was related to my sister in law being on a T-mobile network or just because she was using a different phone.
However, last night, a friend mentioned exactly the same thing. Out of three text messages I've sent, two came in blank, no text.
My theory: We both text in English and Spanish, therefore we have two keyboards loaded on the iphone, so we can switch easily. I have a feeling the special characters in the spanish language is what deters people with other phones/different network to receive them properly. I will switch my keyboard back to English only and post my results.

My gf's sister says that she's been getting blank texts from me recently. i also use dual keyboards but my GF never says that she gets blank messages. It may be a difference in networks. IDK..