Bad service from Vodacom

We pay for a 20Mbps download & 2 Mbps upload from Vodacom. For the last two weeks we have reported numerous speed test of under 1Mbps downloads speed. Vodacom ignores our email with our speed tests. I feel that it is not fair to pay for a service we do not get. We are trying to run a business and really struggle with the service we get from Vodacom. When we decided on a Service Provider for fibre we were going to go to Telkom but then decided that Vodacom would be better. This might be a mistake. Please help. Our Vodacom acc no. is I ********** -4. Regards Helen Trauernicht