Deregister my iphone with non-iphone

I cannot receive texts from people that have iphones because I no longer have an iphone. I am trying to deregister it using the link on the apple site but the last step requires a confirmation code that I am not receiving neither by email nor by text on the cell number that I have registered with Apple but is no longer an iphone. Where is this confirmation code supposed to go and how do I get it without an iphone? Please help.