Appalling ABSA idirect customer service makes it impossible to cancel a policy

After years of being a loyal ABSA idirect customer, I tried to renegotiate the terms of my car insurance when the policy came up for renewal at the end of March (since I have been a customer for years and am in one of the lowest risk categories of policyholders). But instead, ABSA idirect increased the premium. So, in response, I found another insurer who is charging half the premium. However, although I was told by a consultant that I could cancel at any time with no notice, I have been unable to cancel my insurance policy. In the last 8 days, I have called three times, waited almost forty minutes in total only to be told that the consultants cannot cancel the policy but that I had to speak to the "retention department", who are in turn, uncontactable. On two occasions, they undertook to phone me back in 48 hours (which in itself would be considered unacceptable turnaround times), but to date, no one has even called me. On the third occasion they hung up on me. I subsequently mailed twice and even left a call back on their website and not once has anyone called me back. My debit order is due to come off tomorrow and given that they have not cancelled the policy or stopped the debit order there is a possibility that the debit order for my new insurance is going to bounce. I have seldom experienced such shocking service and my only consolation is that if I can ever get this policy cancelled, I won't have to deal with them again.