Alll communication is ignored

I received advise of an increase in June. When I queried why I pay so much per month for an old car (and the excess is also a little excessive), I was sent an email with no explanation, just that they have reviewed my policy and will offer a lower installment, which I had to email my acceptance within a certain time frame. So of course I emailed that I accept. When my next installment came off, it was the higher amount. I queried this a few times, and received no response. Just ignored. I sent another email stating that this must be seen to immediately or I will take this to Hello Peter and look at an alternative option for insurance. Ignored again. I still have had no response to any of my queries - sent from 2 different email addresses now. I need to cancel insurance for one of the cars as I am selling it, but seems I'm stuck paying that forever too... They just ignore all correspondence. My correspondence is done via email as I cannot make personal calls while at work. I am looking into other options for insurance (which is extremely frustrating because I'm receiving spam all day from various companies).