Billing issue

I luv the fibre, works well no issue. The issue is the billing. They started to double bill me. I contacted the call centre towards end Feb 2021 and still has not been sorted. My CAS-515212-H2J5F5. I call almost everyday and get told it will be dealt with, we are now end May 2021. I just received an invoice and it is still incorrect. I even emailed a project manager Sinawo, did not have the decency of acknowledging my mail even. This is as the last resort, writing, hopefully someone will call me and sort this out urgently. Thank You.