iphone 6 voice recognition not working

I have an iphone 6 and have had it since October 2014. For about a month now, the voice recognition option does not work. I like to use it rather than texting, and emails when I'm on the go and it's frustrating that I can't figure out what's wrong. I have looked through other threads to try and figure out what else I might do. So far I've:

• rebooted (hard reset)
• double checked that all my settings are correct re Siri and voice recognition
• checked that it is not a problem with earphones v. no earphones. Doesn't appear to make any difference
• Siri doesn't work either
• Checked the microphone to make sure it's not blocked or something

I can use the phone feature just fine.

It just seems to be the voice recognition feature that doesn't want to cooperate. If you have any ideas please let me know!

I'm taking it to the Apple Store next week since I have run out of my own ideas... Thanks! 🙂