Telkom not Delivering

In December myself and a friend moved in, we transferred his line to our current place and immediately checked on the Telkom website for an upgrade and what our max line speed for that area was, on the website it was stating 10mbps is the max line speed that we would be able to get. The sales agent agreed that we could get 10mbps when we did the upgrade, whilst when the technician that installed the ADSL said it was impossible and that we could only get a 4mbps line .. currently we're sitting on 6.1mbps but we keep on logging calls and Telkom keeps on closing them saying the issue is resolved, Sunday we received a phone call from a technician asking if the internet is working, so we said yes it is but the speed isn't right, as soon as he heard that he hung up and closed the call, the exchange is in a \popular"suburb"