Impossible to cancel a service that that been runnig for over 9 years

I send a messages cancelling my tracker in a vehicle I owned for 10 years,after I have spoken to the cancellations department,they confirmed that I can cancel the service with 30 days notice.I send the email in January its been 3 months they are still taking money from my account I have phoned and email them numerous time to fix this.this morning I receive and email. Please note I bought the device cash as to not have a contract.This Morning I received an email telling my my contract only runs out 02/06/2020.I find it every unlikely that my cont tract can be for 9 years and 9 months even tough I paid the device upfront