Line Still a problem 3 months later.

I have 4mb adsl line. The line syncs correctly however a speed test indicates that <br> the line is under 1mb. I have had this problem since the beginning of December. <br> Here are the ref numbers of the calls logged since beginning of Dec : <br> 43CRK171215,318CRK201215,1277CRK211215,240CRK221215,28CRK180116,17CRK190116,<br> 1282CRK210116. <br> The above was logged on HelloPeter on the 22/01/2016. <br> After the social team picked up the call it was resolved the same day.<br> Problem started again on 28/01/2016 - call 801CRK280116 logged. It was <br> resolved on 30/01/2106.<br> Problems started again on 2/02/2016 787CRK020216. Logged hellopeter on ***.<br> Problem fixed same day.<br> Problems started again on 16/02/2***CRK160216. Tired of waiting. Upgraded line to 10mb on 19/02/2016. Line upgraded on 23/02/2016. For some unknown reason on the 24/02/2016 line downgraded<br> to 4mb and original problem is back. <br> It is now 3 months and I am still waiting for the line to be fixed. What must I do get it fixed ? Whom can I call ?<br>