Ask them to listen to the call. If you was told that you would get X amount of minutes and X amount of texts on this new tariff, it doesn't matter about the internet usage, as they never told you that you will get it.
Firstly, you get to move back to your old tariff within 14 days, if you are still within 14 days of the tariff going through.
Secondly, so you have been put on to the £25 24 month tariff? Okay so one of two things will have happened. You will have either been put on the online tariff with a standered o2 to o2 calls bolt on, if this is the case you can swap the free o2 calls for free BB usage. Or, you may have been put on the offline tariff with no free bolt on, if this is the case, phone up and be persistant. Agents on the customer services department cannot do this, however either there manager can, or someone on the upgrades team will be able to.