How to Stop Your Old IPhone Getting Your Text (SMS) Messages
What happened to me recently was that I decided to give the Android phones a go, and upgraded from my iphone 4S to a Galaxy S4. (whats the go with the letter S) Then for a day or so after the change I noticed I wasn't really getting any text messages. A quick look on my old iphone which I had still on my desk, and there they all were.
It's strange you have to admit, that I have removed the SIM card from my phone, and it is still getting text messages. Here is the reason why.
Our wonderful friends at Apple, in the name of convenience, decided to help all iphone users out by sending text messages via the internet instead of the regular method over the phone system. Of course they can only control apple phones, and so what they do is that if you are sending from an apple phone to another apple phone, they will send it via internet protocols instead.
The details of apple iphone users are stored in their directory/database at Apple Inc Headquarters (or wherever their data centre is) and that helps route the messages quicker. The benefit of this, is that you can message other apple users on ipads, ipods and other devices using the same technology, even though many of them won't have any telecom connection. All good so far - and it saves money too.
However big problems happen when you decide to either leave apple (in my case) or even upgrade phones to a different iphone. Now there is a situation where your details are in an apple database but your sim card is in a new phone.
So my wife (using her iphone) goes to send me a text message. Her apple iphone uses the technology to send it to the apple database which shows that I also have an iphone (except I now don't) and it forward it using the internet to where my phone used to be, but of course I don't get anything. However because my actual old iphone is still at home (connected to our wifi) it gets the text messages via the internet.
It's not very helpful when she needs me to bring home milk and I don't know until I get home without the milk.
Depending on what exactly is the situation here is what you should do.
If You Upgraded iPhones
If you upgraded phones, you need to go into your old phone, into the settings and turn of iMessenger. Then go into your apple device account and disable your device after that and from that point on, you will not receive any more messages on your old phone. You can manage your settings in your new iphone under iMessenger.
If you Upgraded to Android
If you left apple altogether, then hopefully you still have the actual phone you used. Before removing your SIM card, go into settings->iMessenger and disable the phone number in there. Then you can go ahead and remove the SIM card from your phone. Then go into the apple device manager - login with your apple id and disable your phone from there and all should be good. Now you will be able to receive text messages from other apple users.
If however you removed your SIM card before you disabled the settings, and you are unable to put it back in... you are in a tricky position. You will need to call apple support for help, and you may need to pay for the support. I hope that doesn't happen to you.
Is all of this annoying? Yes. However its better than starving to death.