problem in sending texts to o2

[psaw]

hi I have just got a new contract on my old sim and together with my partner (who got a new sim) we were advised to go for loyalty discount by texting to 21500 as we live at same address and have been with o2 for years 

Both of us have tried to send o2 texts and we get message saying texts not sent ,please tap to try again ------

Texts to from  other numbers are working 

What's going on here .Anyone have ideas how to fix this 

[Bambino · Accepted solution]

@psaw If you try O2 via social media they should be able to help you with this:
Facebook (https://o2uk.co/O2CFB), Twitter (https://o2uk.co/O2CTW), or Instagram (https://o2uk.co/O2CIG)
Or you can call them on 0800 081 0255