Missed call alert from o2

[Baz2]

You missed calls from me at 12:00, 12:00 and 12:00 02 Mar.This is a free Call Alert from O2. To disable this dial 901, press *, then option 4 and option 5.

Hi, I was on a call when my phone cut out. The caller said they had tried calling as I had to wait a moment while it turned on.
I noticed the above message in my inbox sometime later.
The missed calls are from the same person yet are at the exact same time.
Can anyone explain?
The o2 site will not recognise my number as valid, I tried to contact them with this number yet it is not recognised.
Any help would be much appreciated.
Thanks

[MI5]

I’m afraid you will need to keep onto customer service to fix this for you.

[Baz2]

Will try again, thanks.

[Baz2]

Customer service can’t help, they don’t know what is happening.
Thanks

[Anonymous]

@Baz2 You may have to go down the complaints route then 

https://www.o2.co.uk/how-to-complain

[MI5]

It's their job to help not ignore it.
@Martin-O2 @Marjo can you get someone who is more willing to assist please?

[Baz2]

I agree M15, after calling again the guy asked me a lot of questions to in the end tell me to turn my voice mail off then on.
No help really.
o2’s own system says my number is invalid. Unreal

[MI5]

Unfortunately customer services have lost their way of late.
Rather than trying to help with the more difficult problems they just try and get rid of you to move on to an easier problem.

[Baz2]

Talk about infuriating, o2 have caused me undue stress due to the shear amount of times I’ve had to explain to different techs.

[Martin-O2]

Cheers for the mention @MI5 

@Baz2 I'm sure we can get this sorted for you. I'll need some additional info so we can look into the cause so I'll send you a private message. Please get back to me when you have a minute.

[Baz2]

Hi @Martin-O2, same number called and my handset shutoff again. When it rebooted there was no log of it in recent calls?
Line sounded funny, a faint clicking.
Not good 😡