How do I stop my BIXI subscription?

I'm currently subscribed to BIXI, but I'm finding that I'm not using the service as much as I initially thought I would. I'm interested in knowing how I can go about cancelling my subscription. Do I need to contact customer service directly, or is there a way to do it through the app or website? I'd appreciate any information you can provide on the steps I need to take to successfully stop my BIXI subscription.