Failure to Contact customer to change Banking details

Been sending emails to Liberty to change my Banking details which hasnt been done. I've also asked them to contact me which they have not done. I have also lodged complaints and nothing has been done. My Life Insurance Policy is now at risk of being cancelled. I have been a Liberty Life customer for 6 years and this is how you handle your Clients? Im definitely taking my business elsewhere. Please contact me urgently.