DRI*Spyhunter review: Billing & renewal

In April 2015 I got something I was billed for from above company. At first it was for $75.75. I see from my records that I got credit for what I thought was concerning this whole sham order. I received a credit of $43.29 at that time along with a cancellation notice. In Sept 2015 I got an email saying it would be renewed if I didn't contact them before that. I checked with my son who said it was nothing I needed and thinking I had already cancelled it I didn't worry about it. Before I could get in to cancel (again!) a charge is now appearing on my credit card ($32.46). From what I can tell they only cancel one portion of an order and then you still have another order number to contend with. I DO NOT want any of this item and how can I get it cancelled once and for all?