Broken internet line 3 months (2.3mbps on a 6mbps)

We ask for our line to be transferred to our new house using the existing line early in October 2015 for December. We move in with a 2 mbps line, not perfect but worked. We then upgraded it to 6 mbps early January. They upgraded the line butran at a maximum of 2.3 mbps half of what it should be. We called the customer service and had 2 different guys come and fix the line each time saying that it worked fine. It was not. We then had another guy come out and say that the line into our complex needed replacing and said it would be logged. 2 weeks went by and nothing was done. We called again and said our line needed fixing. Another person came out, did nothing and said our line needs to be replaced. Nothing happened. We then got hold of the customer review centres and told them what was wrong and they said they would come to our house for a meeting to see the issue. She arrived 5 hours late, no warning no apology. She then told us there was a fault and would send a technician the next day. The technician never came. I got a phone call then from a technician asking if there was still a problem, I said yes. He said he would contact his manager and get back to me. He never called back.