Overcharged under serviced!!!

I tried to cancel my Vox subscription of 100/100 Fibre line for almost a month due to the fact that my line was throttled to 50/50. Retentions contacted me and advised that we get the technical team to contract me. After waiting Ruan contacted me and after some trouble shooting, we came to the conclusion that the Wi-Fi signal is cause the problem due to range. He advised me to get a Deco extender with a range of 1500 meters to boost the 50/50 line. Which I did however he told me that we are actually running on 25/50 and that he will log it for investigation. Two days later and we are still struggling with signal. The line was restored to 50/50 but it stil seems to drop constantly and when I am in my yard the Wi-Fi signal doesn't reach! To top all of this, I have been emailing, whatsapping and calling Vox to find out what I must pay. NO ONE IS RESPONDING. I HOWEVER RECEIVED THE INVOICE OF R1894. 41. STILL WAITING FOR SOMEONE TO RESPOND, I HAVE NOW BEEN SENT A SUSPENSION WARNING BECAUSE I HAVEN'T PAID YET! I REFUSE TO PAY THIS AMOUNT AS IT IS INCORRECT! I AM REQUESTING A CANCELATION BECAUSE THAT IS THE ONLY WAY TO GET SOMEONE TO RESPOND!!!!! 😡😡😡 SO HELP ME GOD IF THEY SUSPEND ME I WILL SUE!!