Where is the problem?

[tsume]

My ADSL line hasn't been syncing to the DSL for some days now. Every time I tried calling Telkom customer service this week I was on hold for 20+ minutes, granted this was in the afternoon and the many people called but WTF! Anyway I finally had time to call just now, reported that my DSL light is flashing. I was told that everything from the exchange is working and traffic seems to be running fine, then was told I should check with my ISP (Afrihost). My Afrihost account is active but no IP session (of course theres is no IP session if the DSL is not even working).

Can anyone give a guess what could be wrong? Could it be the modem (duoPlus 300WR)?
The phone line is working perfectly as I can make & receive calls.