O2 Password rejection on smartphone

[JohnWilliam]

I can access MyO2 usingmy laptop without any issues, but if I try on my phone (with exactly the same info) I get the 'Username and Password do not match' message! I tried over and over with no luck and I do not want to change the password. In fact if I try to changing the password to the correct password I get a notification that the new password can't be the same as the previous one (!) so why does O2 not work with the registered password, just as it does using the laptop?
I don't know why this should be, but wonder if it could be due to the different keyboards - one of my password characters uses the shift key (on the laptop) but the smartphone keyboard does not use a shift key to produce this character.

Also, it is not helpful that O2 does not enable you to view a password!

[Cleoriff]

@JohnWilliam 

I'll ask one of our account advisors to help tomorrow.

@O2Lisawill be on at 8am.

[O2Lisa]

Morning all, happy Friday 

Thanks for the tag @Cleoriff, I'll message you privately @JohnWilliam and look further in to this for you

[Cleoriff]

Thanks @O2Lisa 

Also, the rota is out of date. We have nothinng for today or the weekend. Could you let someone know please?

[O2Lisa]

Yeah of course I will @Cleoriff 

Sorry about that

[Cleoriff]

Thanks again @O2Lisa 

[O2Lisa]

You're welcome @Cleoriff 

[JohnWilliam]

I was advised to delete the my02 app, (but given no advice as to how this can be done) and reinstall it.
I have tried doing this over and over again, but always end up with the phone not accepting my current email address and password. (I deleted the app by forcing stop, clearing cache and data and clicking uninstall).
I am also getting multiple messages a day saying I have a new voicemail, number unknown.
How do I prevent this? I do not have voicemail enabled on my phone and do not want a voicemail service...