I have just got an IPhone 13 Pro Max on Vodafone network.
When I send text message to “only some people “ they received the message about 4 times.
Is this a setting on my phone or something else?
I am not an expert on such things, but I’m confident it’s not a setting on your phone. It actually sounds like some sort of network issue.
If it’s ongoing and you need to troubleshoot it, maybe start by trying to see if there are common characteristics for the people who get the multiple messages. You may find that they’re all with Vodaphone, or all with Telstra, or something along those lines. Once you have a common attribute, maybe contact Vodaphone.
If you can’t find any commonality, i.e., they’re all on different networks for example, then I’m not sure what to suggest, sorry. Let us know anyway. If you report back it may help someone else in the future.