How much is the actual bill for? 17.99 or 9.87 or 27.86?
If it's the last one, then it's pro-rata billing.
Have a look at the dates on the bill and what time/dates each of those charges applies for.
Anyway, Orangebird will probably be in shortly to dispel my answer and say it's something to do with the voices I keep hearing, then give you a proper answer
