Unable to cancel my vps service

Hello, I have already disabled auto-renewal in December but received an email in January that my account is in debt for the monthly amount. I did not want to continue using the service and that is why I already disabled automatic renewals. I had to pay for this month so I am not in debt even though I am not using it. How can I cancel it and can I get my money back? It is not fair to force me into paying by putting my account in debt. I disabled automatic renewal in the middle of December. I just want to be done with this service.