VOX telecom - Harassment

I called VOX (in March 2019)to arrange wi-fi installation then cancelled the next day as I found out that our complex uses Afrihost. Every month VOX had sent me an invoice for installation that they didn't do. Every month the amount owing gets larger and now they say they are going to suspend their services - What service?!! - I have tried for three months via e-mail, phone and if I had a ***eon.... To sort this out but they take not one ounce if notice.