Not receiving texts from iPhones since switching to Anroid

Since switching from an iPhone 4 to an Android phone, all texts from iPhone users go to my old phone. Things I have tried:

1. Removed my iPhone from my support profile.

2. Changed my Apple ID account email address and password.

3. Turned off iMessage on my old phone.

4. Got friends with iPhones to delete me from their contact lists and re-add me.

Have hard rebooted both iPhone and new phone after doing these.

What else? I can't carry round an old phone and connect to wireless just so I can pick up texts!