@CGHave you checked your bank account to see if 2 direct debits are setup to o2?
I had this once where my then bank decided 2 direct debits to the same company was a mistake and cancelled one of them, it was very helpful of them.
Also depending on how close to your billing date you upgraded depends if the 2nd Direct Debit was setup in time.
If you call o2 on 202 or 0344 809 0202 and when it asks why you are calling stay silent for 15 seconds and follow the options.
- Xperia 1V - o2 and Spusu
- Pixel 8 Pro - o2 and Vodafone UK