HTC — complaint not solved on time

I am using htc desire 816 dual sim phone, There is some problem is creating in the phone then i submit my phone to sec-18 service centre and the employee will say sir after 15 to 18 days you will receive your phone from service centre but at today the phone is not okay because there is delay in the spare from company side and loose work done and wrong communication by the employees of the company and the handset i not receive to me.