Very Slow ADSL Speed

I have a Telkom line *** with an accompanying ADSL line. Although my account has never been in arrears, the speed on my ADSL is so slow to the point that trying to access a Website is an insurmountable task due to the extremely slow speed that causes tne system to simply hang all the time. It is a futile to call the call centre as calls are normally not answered due to \high call volumes"and one just simply gets cut off after holding on for in excess of one hour. Can someone from Telkom kindly assist in resolving the very slow speed of my ADSL. I am paying for a very expensive service and in return expect to receive service of a high standard"""