IPhone won't send texts to non iPhones

Question

I can send texts to iPhones as either iMessages or SMS messages. However, I can't send texts to contacts who use other mobile devices (ie. Not an iPhone). However, I can receive SMS messages from non iPhones,
I've reset network settings and nothing has changed.
I only purchased my phone a week ago and have had this problem since new.
Any ideas anyone? Your help is much appreciated
Note: iPhone 6 16GB using iOS 8.1.2

Answer 1

Hi Rhys1998,
Happy New Year!  If you are not able to send SMS messages to a non-Apple phone, try these troubleshooting steps:
If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support
http://support.apple.com/en-us/HT204065
Check your device settings
Make sure that you’re connected to a cellular data or Wi-Fi network.
Go to Settings > Messages and make sure that iMessage, Send as SMS, or MMS Messaging is turned on (whichever method you're trying to use). Learn about the different types of messages you can send.
Check the recipient's contact info
Make sure that you're using the right phone number or email address. 
Go to Settings > Messages > Blocked and make sure that they're not on your block list. 
Restart your device and check for updates
Restart your device.
Check for a carrier settings update.
Check for an iOS software update.
Check the system status for iMessage
Go to the Apple Services System Status page and check iMessage.Turn iMessage off and back on
Go to Settings > Messages and turn iMessage off, then back on.Sign out and back in to iMessage and FaceTime
Go to Settings > Messages > Send & Receive, tap your Apple ID, then tap Sign Out.
Go to Settings > FaceTime, tap your Apple ID, then tap Sign Out.
On your iPhone first, sign back in to iMessage and Facetime.
Sign back in to iMessage and Facetime on your other devices.
Reset your network settings
Tap Settings > General > Reset > Reset Network Settings.Back up and restore your device
Use iTunes or iCloud to back up your content, then restore your device. 
Send messages with your iPhone, iPad, or iPod touch - Apple Support
http://support.apple.com/en-us/HT201287
What's the difference between SMS/MMS and iMessage?
SMS/MMS lets you send text messages and photos to other cellular phones or devices. iMessage lets you send text messages and photos to another iOS device over Wi-Fi, without worrying about text-messaging charges (cellular data charges may apply). 
What do I need to use SMS/MMS and iMessage?
Here's what you need to use SMS/MMS and iMessage:
SMS/MMS: A text-messaging plan. Contact your carrier for more information.
iMessage: An iPhone, iPad, or iPod touch with iOS 5 or later.
Can’t get text messages from an iPhone - Apple Support
http://support.apple.com/en-us/TS5185
You can't send SMS or text messages to a non-Apple phone (such as an Android, Windows, or BlackBerry phone), because the messages are sent as iMessage
This can happen if you used iMessage on your iPhone and then transferred your SIM card or phone number to a non-Apple phone. If you didn't turn off or deactivate iMessage before switching to a non-Apple phone, other iOS devices will still try to use iMessage to send text messages to your phone number. Follow the appropriate steps below to resolve the issue. Likewise, if you can't send someone a text who used to have an iPhone, having them follow these steps should resolve the issue.
If you still have your iPhone
Put the SIM card you transferred from your iPhone back into your iPhone.
Make sure that you're connected to a cellular data network (such as 3G or LTE).
Tap Settings > Messages and turn iMessage off.
If you don't have your iPhone or if you can't turn off iMessage
Use the deregister iMessage webpage. For more information, see Deregister iMessage: Frequently Asked Questions.These steps won't deregister your phone number with iMessage
Logging in to My Support Profile and changing your password or removing your phone number
Texting STOP to 48369
Resetting your network settings
Changing your Apple ID password
Last Modified: Nov 10, 2014
 I hope this information helps ....
- Judy