I used the following senence and it doesn't look right to me but i can't phrase it with out the "not" because it changes the entire context.

"I can't not type in complete sentences".

I was referring to using one word abreviations for text messaging. Help please!!!

Just don't say it like that at all.

"I have to type in complete sentences," states the same thing in proper English. You can say it any number of ways, but the double negatives (I'm pretty sure) are not the way to go.

Hope it helps.