512 is acceptable speed for a 1024 line at neotel

Since Jan 2015 ,when I reach my FUP my line speed is supposed to be halved.Thats from 2mb to 1mb.I dont have a problem with that .But what I find since Jan and been trying to get into their heads is that I get speeds of up 512kb.Neotell argues that its an acceptable speed for a 1mb line.Strangely enough when I was on the 1mb package I did in fact receive 1024 kb speed. I've been trying since Jan to get this resolved and every month they tell me stupid stories like I have a website open (c'mon a site that consumes half a meg of bandwidth) and they will get back to me.Its September now and their new response is I must monitor the line and if the speed drops they will investigate.In my book 2Mbps line is 2048 ,1Mbps line is 1024 , 0.5Mbps line is 512.I have tons of emails I can forward .Ran my cell bill up trying to get a response.All i get is Apologies for the delay in response and then they say we will investigate and that I am getting acceptable speeds.I feel I must move on to a Service Provider that has the expertise to tell ,measure , interpret line speeds and gives support.PS - 512 is not 1024