Loyalty discount. Text to 21500 not working

[viridis]

When texting loyalty to 21500 you get the response:

Thanks for your text. We just need a few more details and then you're good to go. Please can you send us the keyword LOYALTY, your existing phone number and all additional Pay Monthly Phone numbers to check your eligibility

So, I respond with the text of: loyalty *main number, *upgrade number.

Now, normally you get a text saying:

Thanks, we've just got to check things over, and we'll text you in a day or two 

But, I'm getting this response:

O2: Thanks for your text. We can now start to reward your loyalty with 10% back on all your top-ups with O2 Rewards. We'll text again to confirm everything soon

[MI5]

FUBAR innit

[jonsie]

Oh dear, typical O2 [Removed] systems