Unknown mobile number linked to my account

[Harry02]

I received a message from O2 "O2: Just to let you know, mobile number 0759*******, which is linked to your My O2 account, has contacted us about your account. Unaware? Call us on 202" - it gives me the full number I just thought it best not to expose, I called 202 about it but the robot you have to talk to is useless and after jumping through all the herdles it says goodbye to me, how do I unlink this number from my account? I get texts about their bill being overdue also. Any advice?

[Bambino]

Deleted by me

[Bambino]

@Harry02 Call any of the numbers in the link below. Select the Fraud option to get through.
https://community.o2.co.uk/t5/Other-Products-and-Services/Coronavirus-Covid-19-Community-Help-and-Su...