Incorrect Speed for Broadband service

We are currently on a 4mbps line which we upgraded from a 2mbps line. Speeds were fine and constantly acceptable. We decided to upgrade due to good service. Our speed test done via LAN from POE indicates 0.6mbps DL and 1.4mbps UL after upgrading. THIS IS LOWER THAN OUR ORIGINAL 2mbps line.These speeds mentioned have been consistent and we have sent through numerous screenshots to consultants at Neotel AND NOBODY IS ABLE TO RECTIFY. We hold on for 20mins at a time either to be cut off or Neotel wanting to question the speeds. I am paying a thousand rand a month for this service and it is breach of Contract!! I am not wasting another cent trying to explain this issue to a different consultant everytime. I expect this issue to be rectified pronto. Latest reference numbers received are FCR*** & FCR***. Our e-commerce business is unoperable with this service provided and our business is now affected.