I purchased this add on on October 22. " Added* US Unld min/sms $45 30day Price per Month:$45.00 Service effective on October 22, 2016 ." for my iPhone 5S. Now that we are in the States, I cannot send texts unless I have Wifi. My texts want to send as an Imessage and when I change it to text message it still doesn't go. I get a red ! and not delivered message. My Roaming is turned off and my LTE is enabled. What is wrong, please?