ADSL line down often, no help

My ADSL line has gone from 3 mbps to 0.5. This is the second time in 2 months. I have paying guests who need internet urgently so I dont have time to wait on the phone for an hour with no answer, which I have just done. I need the line up again this evening. Last time Telkom was quite efficient but it seems they have fallen back into their old ways. This has a negative impact on tourism in SA. My guests are all business people from Brazil. Please sort this out ASAP