Problem with Samsung phone

[LezLee]

Not strictly speaking, to do with music or radio, but in the vague hope somebody techie can help.
I have a Samsung Galaxy S4 mini phone and suddenly find my sister is not receiving my texts. They are successfully being sent but nothing happens at her end even though I am getting hers to me. I've tried my nephew, niece and 2 friends with no problem. Neither of us has changed our phone or done anything at all different. Hers is a very basic Philips 'unsmart' phone, not even a camera or radio.
I've tried the online help - it seems to be a fairly common problem - but no luck. I thought of trying the +44 prefix but can't find a + sign anywhere on the keypad!
I've been able to speak to her from my mobile to hers so it doesn't seem to be a number problem. Any ideas?

[Forget It (U2079353)]

Might the missing sms's be in the spam folder?

to dial a plus +
try a long press on the zero 0

[LezLee]

Thanks. No, nothing in my spam folder. I didn't realise I had one! I very rarely use the internet on my phone. The zero just brings up a load of zeros.
Anyway, I've now found I can just use 44 without a plus sign and the message is sent, but she still doesn't receive it. I'll just have to answer her texts verbally.
I was wondering, as I've still got my old phone - nothing wrong with it, I just wanted to update it - if I move my SIM card from my newer phone, will I lose everything?

[johnb]

Am I correct that you can send texts to other people and they receive them OK?

And you can speak to your sister using the same phone number that you send her texts on?

If so it suggests that the problem lies with your sister's phone or set up.

Can she receive texts from other people?

She hasn't accidentally blocked your texts by any chance?

[LezLee]

Yes, she can do all those things. I'll ask her about blocking my number, she could have hit a key by accident. My nephew's quite tech savvy so he might be able to help when he takes the grandkids round.
Thanks.