Poor service in trying to extend my current ADSL to uncapped

I have been trying for the past 3 days to make contact with Telkom to upgrade my current ADSL from limited to uncapped. Every time I phone I hold on between 10 - 15 minutes and I eventually give up. Trying to log a complaint is impossible and trying to speak to someone not an option. I find them absolutely pathetic and whilst I have generally in the past experienced very good service, this time I am afraid to say has been one of the worst and most frustrating ever!