Annoying iMessage issue

Ok, so I'm having a really annoying problem with iMessage:

Me and my girlfriend both have iPhone 5S's (7.0.4), and we were both able to use iMessage with no problems. iMessage is kind of essential for us because she lives in the US and I live in the UK. She came over to the UK for a month and I got her a UK SIM, just temporarily, so she could use the phone over here - again, iMessage still worked fine but now to a new number.

The problem is, now she's arrived back home and put her American SIM in, I can't imessage her. I can only SMS, yet she CAN imessage me. We can both imessage every other iphone contact in our contacts list without a problem, it's just my UK phone that can't send an imessage to her US phone.

We've tried the basics of turn imessage off and on, resetting networks, hard reset the phone, our send and receive lists match (both phone and email, starting conversation from the phone which is what we've always had). I'm just totally lost. I have no idea why it's not working, it just doesn't seem logical at all.

Sorry if any of this doesn't make sense, I'm very tired and just wanted to get something out before I sleep so I can hopefully have a response by morning. If anything needs clarifying, just let me know.
Thanks

Rich74 said:

Have you tried deleting the number then adding it again in contacts?

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Yes, i've tried that and still no luck annoyingly

ugcop said:

I had a similar issue in that after changing a phone number in a contact, every time I tried to send a message it would pull up the old number. It seems that old data has to be overwritten before it stops coming up in a search. I used an app called ishredder. It overwrites all open space in memory. At times it is free but right now it is $1.99

I think the problem is your phone by the way.

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I was assuming the problem was my phone, but i just can't see why it's suddenly deciding not to work??

It's not that it's pulling up the old number, it's just that it won't recognise that it's an iPhone and that it can send an iMessage to it, EVEN THOUGH it allows iMessages to be received from the number in question.

navodwickra said:

Reset network settings

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In my original post i state that i've tried this

Tumbleweed666 said:

Have you tried deleting her from your contacts and then adding her back in again with only original number in?
Also, can you iMessage anyone else? Is it just her?

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I've tried this, and as stated in my original post we can both imessage every other iphone contact in our contacts list without a problem, it's just my UK phone that can't send an imessage to her US phone.

bkribbs said:

I guess that's different but similar. I figure deleting the thread and contact would add it but I don't want to do that so...

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I'd quite like to keep all of the message history if possible, i like to hold onto things...

Xenc said:

Try sending an iMessage to her Apple ID instead of her phone number. Assuming the address is enabled in FaceTime Settings, she'll receive the iMessage on her phone.

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But then won't I lose all of the conversation history (because it'll start a new thread) and it won't be able to send an SMS in the event that one of us is offline?

Xenc said:

Assuming it works, it would at least allow you to message one another when you have a network connection. You wouldn't lose your previous message thread.

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So this would be a temporary fix, yes, but ideally i'd like to fix the problem that is the phone number

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The even weirder thing is, if i delete her email from contacts, i can still FaceTime her on her number alone

I tried deleting the thread and that didn't work, then i've tried restoring the phone and that still didn't work... I just don't get it at all