Non functioning device

I took my phone to Samsung Cresta and Omar advised that i should take it to Constantia as Cresta could not fix it.My phone was taken there on the 23 Jan and we were advised that they were going to call after 2 days (only called after 7days).When I inserted my sim card the Phone is requesting a SIM NETWORK UNLOCK PIN.I took it to Cresta as the sim works well with my second Samsung phone.Cresta advised that Constantia should assist as their Technicians are not there. I called Denice (Constantia and she transfered me to a clueless technician.I am not able to be going up and down because of your inadequate employees.My sim card works well with my second Note 3.<br> <br> Kindly advise as I do not have time to waste running around due to your useless employees.<br> <br> <br> <br>