Disgusting service!!!

Called through on the 06/08 to change over my contract to prepaid. Given the date of the 28/09 in which the change over will take place. It's now the 29th and my line is still fully active. Called the call centre between 7-9 times, and the service is appalling!!! Lady who answered my call on 2 occasions, found it very appropriate to cut me off twice, whilst when I called back to speak to a manager, had been put on hold for 7-10 minutes. Finally get through to someone and they advise me that maybe my changeover is stuck on the network. What a load of s***!!! I'm sure that no management will even take the time or responsibility to even reply to this complaint!!