Unhealthy Service provider

I currently cancelled a long time expired contract on my previous vehicle and took a knew contract,and when cancelling that old contract and taking a knew one I was not advised that I will still be invoiced on both old and knew one because that was going to influence my decision on whether to continue with them or not. They company doesn't care about their client, but debiting their accounts. That's it. And now they have debited both old and knew one. Should I have known I would have only made the cancellation and get another service provider because really how do you still charge your active client with cancellation of outdated unit when they are still buying another unit or entering into a knew contract with you.