iPhone 4S - is receiving and sending UNKNOWN - Message not found text messages -

I recently ( in the last 72 hours ) started received messages from UNKNOWN and when looking at the message it showed Message Not Found. Now i have not recieved on this morning - but when sending a group message (which has worked flawlessly for months) all of a sudden they are receiving the same thing and not the message i am sending.

This just happened so randomly and i am wondering what it could be.

I have an iphone 4S (updated)

there are iphone 5 that i communicate with and one of the devices in the thread is a windows phone.

I dont believe it to be an issue with their phones but an issue with mine or my service.

Again this is totally random i didnt play with an setting changes -

I have reset my network settings - it doesnt happen when i get imessages.

Im thinking of restoring my phone to a "new" version and wiping everything clean - but before trying that extreme id like some help!