O2 will no longer use names on some of its mailouts, after the BBC's Victoria Derbyshire programme found it had sent racist hate mail to a British-Iraqi family's home in north London.
Two items were addressed to "Mr Isis Terroriste" and "Mr Getout Ofengland" at the exact family address in Wembley.
They contained free pay-as-you-go Sim cards ordered online in August 2017 by an unknown third party.
O2 said its envelopes for Sim cards would no longer be personalised.
At the time, family friend and lawyer Sura Jawad said the letters were hateful.
"I was completely horrified by it, I thought it shouldn't be normalised. It shouldn't be treated as something that just happens," she said.
Last month, O2 said its Sim card postage and printing was managed by a third-party partner, Williams Lea Tag, and was automated.
Human checks were in place but only once a query had been identified and in this case no query had been raised before postage.
O2 said it was reviewing the whole process but had changed its system so the envelopes for the free Sim cards would no longer be personalised but addressed to "O2 customer".
The family said they were "happy that O2 are taking this seriously enough to change their policies and taking steps to make sure that this doesn't happen again to someone else".
But they added they still felt unsure about which way to direct their dismay at this whole situation, "because there isn't anything that can remedy the feeling of being unwelcome in your own home especially when someone has such a direct means of communication".
In a statement the company said: "It's saddening to think that some members of the public have decided to exploit this free service to send hateful mail."
Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel.