Line upgrade not going through, affecting job!

Please assist. We upgraded our line to a 20mbps line (from 4mbps) last week Wednesday but, despite having received messages saying the upgrade is complete, we are STILL running at 4mbps. We urgently need this upgrade for work purposes and have phoned numerous times to get it sorted, but still to no avail. We just sit with Vumatel blaming Webafrica and Webafrica blaming Vumatel. We URGENTLY need this resolved as I cannot accept my job offer until we are running at 20mbps!