Old Mutual is there a reason clients have hold on to your lines for over 15 minutes other than simple incompetence.?

I have tried contacting Old Mutual a few times now and each and every time I have held onto the line for in excess of 15 minutes for it to be answered. As there was no indication as to when it may be answered, if in my lifetime, other than the tired old phrase, " your call is important to us and an agent will be with your shortly..... etc, etc, I have then put the phone down. Perhaps if you employed more staff the situation could be ameliorated.