Cannot get hold of anyone at repair centre

I have sent my New Blackberry in for repairs twice now, the first time was barely a week after I received it. I got it back from the repair centre and a week later it started again, it switches off and does not want to switch back on, so I have sent it in for repairs again and I asked the branch where I too the phone to about a replacement unit I was told to phone the repair centre when I get the massage that my phone has arrived. <br> I got the message after a few days and tried to phone the number provided on the internet for the repair centre, but I can never get through, it is engaged or I get a message that the subscriber is unavailable.<br> How am I supposed to speak to someone about a replacement phone if I cannot get a hold of anyone?<br> This is unacceptable service and quality of product.