This is entirely normal - until the recent launch of Flexpay, you had one single monthly payment covering your airtime & device. You agreed to pay that cost on an ongoing basis, albeit with a minimum contractual term which you are now finishing.
You are free to move to a SIM-only plan once your minimum term has ended, this can be requested from the upgrade window at 45days prior to the minimum term exit.
New plans sold now have 2 entirely separate contracts - one for the device, the other for your airtime.
