Lenovo — my smart phone touch screen is not working and service center intentionally makes delay saying parts not available

My lenovo vibe smartphone with imei no. [protected], touch screen is not working. So i went to lenovo service center, bhubaneswar, odisha for repairing. Since my phone is in warranty, they said it will be covered in warranty and told to take 7 days for repairing. But its already 20 days gone they are saying parts not available come after 5-6 days. They gave me a contact number which is unanswered every time. I am completely fade up with this approach of the service center and repent why i bought lenovo smartphone.