Large number of unknown international text numbers on latest bill

VincentVega

I have a Talkmobile SIM, paying £4.95 a month.  This month my bill is over £8, which I thought was a bit unusual.  I downloaded my latest bill to find this:



There are two messages from the same 53 prefix number from 20/10/2025 and forty-eight messages from the same 56 prefix number from 09/11/2025 (from 16:25 to 16:51, and then few more at 17:35).  I genuinely have no idea what any of these are (and I can't see anything in my phone's SMS history).  I don't send a lot of texts as it is, and never internationally.

I had a chat with a Talkmobile customer rep, who said that they'd get their technical team to investigate.  They suggested that I set my cap for additional costs to £0, which I have done.

Has anyone else experienced anything like this?  Could my SIM have been cloned or something?

elsien

Have you downloaded any apps which could have sending texts running away in the background? Maybe check all your app permissions? 

Ms_Chocaholic

Several years ago I experienced similar with GiffGaff, over a space of less than 5 minutes I received around 20-30 texts which were all chargeable to my account, I eventually got them refunded by GiffGaff but not without a fight.  Since then I never have any additional credit on my account to prevent extra charges.

Vitor

The two most common uses for numbers like this:

Silent SMS delivered as part of device registration or SIM Toolkit updates. When a SIM is reprovisioned or the phone tries to register VoLTE/IMS, the handset may send multiple hidden SMS to test endpoints.

App-level activation retries. Anything that uses SMS verification (banking apps, WhatsApp, Signal, Samsung/Google account services) may fire repeated “activation” messages if the initial handshake fails.

The rapid-fire cluster on 9 November strongly suggests an automated service attempting retries, not a human, scammer or cloned SIM.

flaneurs_lobster

Is there any content in these messages?

Cloning SIM cards is very hard & illegal, the networks have systems that would pick this up very quickly. 

Unlikely too, would anyone go to this amount of trouble to send what seem to be non-premium texts. Normally these kind of hacks would be sending £5+ each SMS messages to betting or "adult" services.

Networks do sometimes send "provisioning" SMS messages, usually not visible, but that would be a single instance.

ButterCheese

silly question but could anyone else have access to your phone?  Or any accounts linked to the SIM contract?  Long shot, but you do hear of kids unknowingly signing up to things they think are just harmless games

VincentVega

Thanks for all the responses.

To answer a few questions:

1. I can't see any messages from the two dates.
2. No-one else has access to my phone, and there aren't any linked accounts.

I've taken the opportunity to review my app permissions (as suggested above) and to clear out as many apps as i can.  Hopefully this will prevent a recurrence

PHK

Vitor said:

The two most common uses for numbers like this:

Silent SMS delivered as part of device registration or SIM Toolkit updates. When a SIM is reprovisioned or the phone tries to register VoLTE/IMS, the handset may send multiple hidden SMS to test endpoints.

App-level activation retries. Anything that uses SMS verification (banking apps, WhatsApp, Signal, Samsung/Google account services) may fire repeated “activation” messages if the initial handshake fails.

The rapid-fire cluster on 9 November strongly suggests an automated service attempting retries, not a human, scammer or cloned SIM.

I agree, an iPhone sends silent international SMS to it's activation servers for iMessage and facetime. Google does something similar for play store and RCS. 

Normally, carriers zero rate these messages (IE. Don't charge for them) but some of the smaller less capable carriers charge.