Hi @Aine Leonard, your bill can be higher for multiple reasons.
If you’ve recently changed your direct debit date, you may have a longer billing period than usual. More information on that can be found here:
Direct Debit | iD Mobile Network
Otherwise, you may have gone over some allowances (most commonly data). If so, you should have received two texts. One where you’ve used 80% of your allowance, and one letting you know when you’ve used 100%
You should also be able to access an itemized breakdown of the bill via the iD app.
If you do have any further questions on this, let us know here and we’ll be able to send you a PM.
-Lauren