Fedup with non-communication

I am done with this company. They are impossible to reach and/or talj to when you need to sort out a problem. They're very quick to adjust your premium (upward) but when you want to protest/discuss/cancel your policy they are missing in cyberspace. No matter how many emails you send, they "can't open" the messages. They invite you to download their app, it doesn't work. Try to call their calk centre, you're queued forever. I want to CANCEL my insurance... Seems I'll simply have to block their debit order. Maybe then they will take notice. Talk about oneway communication!