ZERO support from Vumatel!

We have been having an issue for the past 2 weeks with our fibre line completely degrading in the afternoons, from about midday. The connection is not perfect in the mornings, with a 20/2 connection, we get about 15/1, but by the afternoon, the ping starts getting worse and worse! It starts to go from about 20ms to 1.5 seconds to about 3.5 - 4 seconds in the evening. The download speed drops to about 1Mbps in the evenings and an upload of like 0 to 0.50. We contacted our ISP when we had the issue for about 2 days, they reported it and they said Vumatel would contact us with in 2-3 days....well, we got no contact! So we called them again and they reported the issue again, well 2-3 days passed again, and NOtHING from Vumatel. We eventually just decided to contact Vuma directly, they reported it, and the following day we got a call from Vumatel asking if it was fixed, before we told yes or no, we first asked them what they had done to try and fix it, they said they had done nothing, and just wanted to find out if the connection was fixed, what kind of service is this!!!!? We have gotten these calls now twice, and both times they have told us that they just wanted to find out if it was fixed without actually doing anything! We are now super fed up with Vuma, and we tried to speak to a manger/supervisor, but as per usual with these call centers, the response is always, “there is no manager/supervisor in”. The service from Vumatel is absolutely disgusting!! There is no support whatsoever, and it would seem they could not care less about there customers!