Calls from private number - claiming to be O2 Belfast call centre

I had a call from someone claiming to be in an O2 call centre in Belfast. He had a strong NI accent and the line quality was very poor, as it if was a Skype call or something. The caller ID number was withheld.

He was trying to upsell me something about smart phones, and asked for details to verify my account. I refused, and pointed out that I wouldn't give information to anyone calling from a private number. He then sent me a text with a sender ID of 'O2', but I couldn't see any sender number, so I was still unsure. I cut off the call politely.

Has anyone else got a call from these guys?

I had to phone 02 Customer Care on Saturday to try and get a sim activated. It was an old sim card so could not be activated. I was told when it was bought and that they had sent a text meassage to it to say unless activated it would be de-activated but then when I asked ok so can you send me out a new free sim card I was stuck on hold and after a few minutes the call was disconnected.

No training and people just dont know how to do their jobs. Needless to say I did not phone them back.

I got a call from O2 on Friday (also showed as private number), the second time in a year. They just wanted to review my price plan etc, it was them as there was no way someone else would know what my price plan was and my monthly spend was.

They asked me to verify my address but no other personal details.