Check your original agreement, @AudreyH0 : it's not always free for the entirety of the contract and hasn't been included in offers / deals for quite some time.
Usually it's just at a discount.
The odd figure you are being charged looks like a pro rata amount. If you are approaching the end of your contract, you'll see odd amounts appearing due to the bill covering some days at the out of contract price.
Staff will respond after the weekend and should be able to see what's been going on. Check back on here later in the week.
Gliwmaeden2, a fellow customer.
