How can I get a refund for my Road Angel subscription?

Hi. i bought this road angel last week from amazon. when it arrived i had to subscribe to yourselves the next day i connected it to my car, it took ages to start working. during the day. it lost contact and kept searching for satellites etc the next day similar , but at times it gives a wrong speed to the one that i am actually doing about 30 mph difference and many other probs so i am returning the road angel and would like my subscription refunded

[Re-Titled by Moderator]