bill gone up

[Adezus]

Recently ,i looked at my bill and is gone up by more than £4 .

i paid £39 and now is £43+.from April

I can't understand why

[MI5]

@Adezus 

It's the annual price increase https://www.o2.co.uk/prices#:~:text=Each%20year%2C%20your%20Airtime%20Plan,the%20general%20level%20o....