No Service

I have the Afrihost MTN sim card in my phone, been happily using it without issues since the launch. No all of a sudden yesterday morning there is no service (can't make or receive calls, no SMS, no data or anything). At first I thought it might be something wrong with my phone so I took a friends Vodacom sim card and tested successful so its not the phone. Logged a call with Afrihost, and since yesterday the only reply I get from them is that MTN is aware of the issue only for certain users, but there is no ETA. I cant do my work as I am on 24 hours support but nobody can phone my number. How can they not know what the issue is after more than a day, and other users also complaining on local forums like MyBroadband. This seems to be specific to the MTN Afrihost users...