Betterbond insurance cancellation nightmare

I have been trying to cancel a home building insurance as from August 2018 as we accepted a better offer from Absa. This has been a long and frustrating journey as we are debited twice by Absa and Betterbond for the same house. Emails are not responded and when I call, I'm sent from pillar to post. To say I'm frustrated is an understatement. Somebody, anybody please help in cancelling this policy and hopingly be refunded!