Vodacom BAD service

I have Wi-Fi with Vodacom -- I was promised a 30meg upload and download -- I barely get 3megs -- I was promised that 20 people would be able to log on. I barely can log in myself. I have phoned and emailed and no feedback. I keep getting referred to one department then the next. I have emailed them since February -- and its April -- I'm on a business account. What business can wotk like this? But they keep charging me the full amount -- Vodacom is essentially *****ing from their clients.