FNB LIFE derailing my policy to default despite calling and emailing. Not updating new banking details

FNB LIFE not responding for debits not going through for a policy that's been standing for almost 2 decades. I changed banking details, sent to them timeously but no debits. Seems they debit amounts they feels are outstanding as a sum amount instead of policy amount into months in arrears. I call amd send e-mails enquirying and no respond on the status to the policy. IS THIS INTENTIONAL TO TRY DERAIL DEFAULTINGS!