Call Centre doesnt answer and bad service

Hi, I took out a new an ADSL/Landline package on the 11/04/2015. I was told that it would be done in 21 days. <br> It has now surpassed that time period. A month later i am scheduled to get the line installed on the 15/05/0215.<br> This is an inconvenient time me for so i have been trying to call the call centre to re - schedule for 3 days now.<br> Holding on with no answer for +15mintues. This is unacceptable. Also they keep on getting my address wrong!<br> My order number is ***A. Account no: CM***.<br> I want to change the installation date to the 22/05/2015.<br> <br> NEED HELP HERE PLEASE!!!