how to talk to a customer advisor to change my bills date and payment date

[Cherry]

I find it very annoying that O2 have changed how a customer can approach the o2 customer advisor. They make it as difficult as possible. Most of the o2 customers are not very tech-savvy, and o2 make it hard to change anything in the account online and not straight forward like it used to be, unless customer walk into their shop and ask for service. Very frustrating.

[MI5 · Accepted solution]

@Cherry 

You need to contact O2.
All numbers are in this guide Guide: Coronavirus Community Help and Support 
Or 202 from your O2 mobile.
Advice from an O2 Guru to get through:
When you call 202, you will be asked for the reason you are calling.
Stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to someone.
You can also try saying "Upgrade" or "Fraud" to be connected to an advisor.