£20 pound upfront discount

[Bumped]

I was meant to get a£20 discount on my o2 upgrade on my handset, but I never received it even though I put the code that on provided. The thing is, ic can't get a hold of anyone to explain why I was bumped out of it because the automated system keeps hanging up on me after directing me to the website. Who knows how to get in touch with them, because the website hasn't panned out well.TIA

[MI5 · Accepted solution]

@Bumped 

To call customer service.
Numbers here Guide: Coronavirus Community Help and Support 
Or advice from an O2 Guru regarding a way to get through:
If you call 202, when it comes to 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.
Say "Upgrade", "Lost/Stolen" or "Fraud" if you have to, to get put through to someone.

[Bumped]

Thanks for that MI5

[MI5]

Good luck