Being double bill

Had the worse experience today with Netstar. A month(1 April) ago, i called in to test my unit, to which the agent said my unit is out of date. And prescribed me to upgrade the my existing plan as it had been a very old plan. Upgrade well went and even installation guy came on site promptly. This weekend i recieved the invoice, which states i am being charged for both old and new products on the same vehicle. After waiting on telephone for lengthly period and being bounced around from one call center agent to another,i finally got to speak to someone in the relevant department. The call center said the reason for double bill is its their cancellation policy to give 30 days notice and made it seem like netstar is may do me a favour by refundiing but her supervisor was not around. The supervisor will have to call me back. No one has called me thus and i would like understand consumer protection act around upgrades vs cancellations.