Been with mweb for 8 years and not a month more

Had a 4meg uncapped premium line for a long time but in the last 6 months only getting that speed for 7 hours a day the rest of the day getting 0.60meg I phone them thy say it is congestion on the exchange so i phone telkom thy say there is non I phone mweb again thy say it is congestion but thy got a plan i have to try a 8meg capped line and with a 8meg line i get 7.20meg for 10hours then it goes down to like 1meg(and a upload speed of 2.5meg some times on the speed test) ***!! I am sick of phoning them so going to change isp