iPhone messaging problem

[Coffee]

My mum has a Nokia and changed her phone number today. My family have I phones. When we try to txt her, our messages are now sending as an i message. This never happened before her number changed. My husband has tried resetting his phone. No joy.  Can anybody help me?? 

[Coffee]

Thanks. Just tried but no, still hasn't worked. 

[kids]

In your Contacts where you have entered your mum's mobile number is it labelled on the L/H Side of the number showing as 'mobile' or as 'iPhone'?

[kids]

Also try as soon as you have sent the message hold the blue bubble and select send as sms (text message)

[Coffee]

It has stopped giving me this option. If I press on it, I only get the option copy or more 

[Coffee]

It's just showing as mobile

[kids]

Is your mum able to send you a sms and if yes what happens when you try to reply?

[kids]

Another thought, you do have a cellular connection when you try to send the sms?

If you are reliant on wifi only you can only send as iMesaages.s

[Coffee]

Hello. Yes I have connection.

[Coffee]

Yes. My mum sends them and I receive them fine.  I have to now turn my iMessages off so I can reply to her. 

[Coffee]

Hello

Just to let you know we went to e e shop and yes this number was a recycled iPhone number. They have deregulate red this number now snd all is good!! Thank you so much for the advice