I do not get what I pay for.

Two weeks ago I did a Line speed test and realised I had a 2.2Mbps line and I actually pay for a 4Mbps line. The line is from Telkom but it is managed by Mweb. Apparently the speed was tuned down and they rectified it. On 15 Feb the past Monday I did a test again and realised it is getting slower again at 3.2Mbps. I just did a test 18 Feb and my line speed is at 2.87Mbps. It seems as if Telkom is slowly but surely turning the speed down as they seem fit, I am fed up with this and I will not pay for something I do not receive. How many other people are being caught without realising. Telkom did send me an sms and said they tested the line and everything seemed fine and I can reply by sending my nr with a @w for working fine or a @f for fault. I sent a @f and nothing is happening but the line getting slower. I will take this to Carte Blanche and then everyone will know.