Call your carrier and verify that there isn't a 3rd party app or something on your account. I did this last month because I decided after trying it, I didn't like att messages. I deleted it but it retaliated and stuck to my acct. My phone would not receive texts at all and they were going to replace my phone but when I set up the warranty phone that didn't work either. I got my old phone back out and called att, they did some sniffing around and found it.
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