Poor Service

The service from Afrihost is very poor, my father and i took out their MTN LTE package but at nights between 6 and 11 our download speed drops from 40mbps to around 0.5mbps so it looks like we are getting shaped, We have contacted them numerous times, the consultants say they will call us back or escalate the problem but nothing happens this has been going on for 2 weeks. my account number A***8 my fathers account number A***3