We are glad to hear that the product is working for you!
The annual subscription of $29 includes server access, mapping licences (Google commercial), software updates (device and website) and support (like this email!) and also ensures we are able to store your data for future access!
The first year's annual subscription was included in the purchase price of your device.
If you do not wish to renew your subscription you can simply ignore the renewal email and the invoice will be credited.
You can always choose to renew at a later time for a different annual period.