Have you enabled call divert from your landline to your mobile? The help article About Call Divert gives details. Might be worth deactivating, checking that call divert is off then switching back on.
Calls to the Mobile Team on 0345 172 0044 are free from your TalkTalk 'phone. Might be worth a call to check that your former TalkTalk Mobile account is fully closed. It should be if you've used the PAC code to switch your mobile number to O2 which I guess you have done because you're receiving the SMS messages.
Let us have an update in due course.
I don't have call divert turned on. I did call the mobile team before to check my account had been closed and they assured me it had. But in My Package, it does say Fast Broadband and Mobile, although if I click on Mobile, it says disconnected. If I call that support number and enter my mobile number, it says it's not recognised.
...TalkTalk support options are here: Contact us. Try LiveChat or Messenger on the MyTalkTalk mobile app (8am to 10pm). Text messages only to the LiveChat agents can be sent to 07403 941724. Just ask to be put through to the Mobile team about an issue with a former TalkTalk Mobile account.
Okay, I got through to the mobile team on live chat, and after being shunted to the landline team and back, I think it's hopefully sorted. There was an outstanding credit on the account which meant that the account hadn't been properly closed. Not sure why that couldn't have been dealt with when I transferred to O2 but anyway...
Does that mean you've finally received the outstanding credit and your account is fully closed? Strange that the original message was "the SIM card in my phone has changed"...if they'd messaged "you have a credit left on your account" and "contact the mobile team" if would have made things a lot clearer.
"All's well that ends well." Or is that another, perhaps better known, comedy of problems!
...these text messages have got to be sent out by a computer system linked to your former mobile account. You'd think that by deleting your former account that would fix it but maybe the account has to remain in place for 12 months after ending.
You'd also think that it would be easy to identify which system is sending out the messages. And to search that system for your 'phone number and erase it.
Thinking about deletion of your data, I'm thinking that you could ask the Data Protection Team to erase your entire data including the 'phone number, and therefore whatever it is triggering the text messages. That would put the onus on TalkTalk to comply with legislation. If the text messages still don't stop that means there's a system still holding data linking to you. Access information we hold on you
Just trying here to think of different ways to try and get TalkTalk to find and erase the root cause of these messages.
Well, the correspondence department have told me it's now being treated as a complaint, and left me a voice message asking me to call them on 0345 172 0088. But I cannot get through on that number because it asks for my mobile number which it then does not recognise. Going round in circles here... I have asked them to call me again, which hopefully they will do.
...Yes, I'm sharing the frustration here. The system plays nicely when existing customer details are offered but isn't set up to readily identify former customers. I'd have expected the correspondence team to know that. But given that your account should still be active for up to 12 months after leaving I'd expect them to locate it.
Finally spoke to someone at the complaints dept earlier, and they passed me over to a manager at the mobile dept, who said there is no way they could be being generated by them and that I needed to speak to the landline dept. After waiting on hold for a few minutes I hung up as I had other things to do.
You couldn't make it up...
Think I've got to the bottom of this. They are being sent by the Find My Phone service which has a SIM change alert. The reason I didn't see it is that unlike on other phones, on my Alcatel handset, that alert setting isn't visible under FMP, and you can only switch FMP on or off. So I guess I owe something of an apology to TalkTalk, although you would have thought someone would have thought of that and suggested it.
Thanks for your help anyway.
So the third-party Find My Phone service doesn't tell you that it's Find My Phone messaging you and spoofs your TalkTalk landline number?
Not very friendly and obviously very confusing.
Still you learn something every day! Thanks for letting us know what was causing the problem.