Harmful business practice acceptable to Telkom

In October 2014 I app**** to have my ADSL line upgraded to a 10Mb line from a 4Mb line. I was infomed that all was in order and the necessary port will be installed. A few days later a consultant phoned me to say the upgrade could not be done as an amount of R5000 was outstanding for an account I had cancelled at the world cup!! I have not received a statement of account from Telkom for this R5000 and was stunned at the behaviour of Telkom. Previously in 2012 when I upgraded my ADSL line I was forced to pay R2500 on the cancelled account so the ADSL line could be upgraded. Again I had not received any Statement of account from Telkom and assumed the matter was now closed. Since Oct 2014 my service from Telkom was very bad - the internet connection was erratic and the land line was also very erratic. Needless to say I cancelled my Telkom as my ISP and went to Afrihost, but now Telkom has cut off both lines and refuses to restablish my ADSL line until such time as I pay R5000 for a line I cancelled some 4 years ago. I pay R1000 every month to Telkom and I suspect Telkom want to bleed me for R5000 before I go elsewhere!!!