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Myself and my wife were both on voxi and I decided to take out a contract phone for both of us and transfer our numbers over.
Anyway the numbers transferred we can phone each other ppl can also text us etc.
However when we do text each other or phone we aren't getting our correct phone numbers showing I think it's the ones the Sims actually were first assigned.
She's got the S21 plus and I've the oppo Reno 4 5g pro.
So when I phoned CS they said at first it was poss a Samsung problem.
But can't be as my phone isn't Samsung.
So I looked on the internet and it seems to be a problem with Android but when ppl on other networks get a new SIM with no assigned number sent out it sorts it for them.
When I have checked the about phone settings and SIM it came up as number unknown. I managed to change it to show my number but still I'm getting the wrong one showing when I text and phone ppl.
I've never had this problem at all with Android and I don't know why it's all of a sudden happening for me.
This situation has come up before if you perform a forum search you will find discussions on this that may help.
It can sometimes be a simple case of ensuring the correct number is in your contacts or about phone section.
Sometimes deleting calling history etc in the phone app can help.
But if a number was assigned previously to the sim card and then a person moves their own number to it then Yes the original number can stay at showing.
A person can ask Customer services for a blank sim card and then perform a sim swap at home to move your current number and tariff to it.
Or wait until the Vodafone Highstreet Store's are open an visit there with identification.
Current Phone > Samsung Note 20 Ultra 5G - SM9860 Snapdragon.
Samsung One Ui 3.1 / Android 11.
There have been previous threads @Arcticwolf with suggestions. These were sending the text as new and not part of an existing conversation, going into the message application and clearing cache and data.
The only thing that worked was a factory reset to clear the phone of previous stored history for the previous number.