Poor service after contract agreed to.

I was called non stop when it came to getting the sale and told that I would be called to install the tracker in 3 working days. But that's a lie. It's been a full week and nobody has contacted to install the tracker that you agreed to. Poor service. Unreliable and disappointing. My banking details was taken very quickly yet no customer service and service from netstar. It's a ****. I would like to cancel this so called contract that no tracker was installed in the first place.