falsely billed

So I cancelled my contract with Rain in July and I did not use their services in August and yesterday I received an email stating that I am in arrears. I then rep**** to their asking how can I be in arrears when I no longer have a contract with them but I got an automatic response saying they "no longer be responding to emails to this address" and when I went to their support page, their submit button is unresponsive on all browsers and on mobi. Can someone contact me ASAP so we can resolve this unnecessary issue.