TERRIBLE SERVICE FROM NETSTAR

Sold my car last year, which insisted on using netstar initially, I called them to cancel and asked for Settlement. They told me they waiting for something from Insurance, Boom they charge me a monthly fee, I have sent them another email to send a settlement letter, NO RESPONSE, now I get another charge. I am going stop that until they call me when it bounces since they canno be bothered on what I want.......why should I pay monthly for something I don’t have, who gives you the right to decide a payment method for me