Lenovo — service center repair procedure not satisfactory

I submitted my lenovo vibe p1a42 at lenovo service center at strength services, wa-88 first floor above icici bank shakarpur, delhi 110092 under the complaint of faster battery drainage problem, the people there had called me twice to collect my phone as it has been repaire but when i went to recieve it they trick me every time by saying that they still observing my phone's issue and they detected some else which needs to be observed; the worst servicing i have ever experienced. Still the phone is not ok, its been 1.5 week.