Motorola Solutions — mobile become unrepairable due to negligence of service centre personnel

Address:	Valsad, Gujarat, 396191
Website:	www.moto-care.com

My phone moto g 4+ had the problem of charging port in build with mobile set i went for replacement of same outside of shop and they repair but again after 20 days it again damaged and become non functioning then i approached to authorized moto service centre at vapi sai plaza sardar bhailawala bank chanod colony gidc vapi 396195 dated 19/07/2017 at 13:33:14 and they handed over me mobile after replacement of charging port dated 03/08/2017 with work done and they shown us at service centre with their own charger that now mobile charging is working. Once we reached at my home i checked it with my charger and find it is not working but when i tighten the wire of charger it start charging so again i contacted to service centre then they said to come centre again. I went again on dated 04/08/2017 morning they told me that their is loosening in charging port, and said me to leave mobile here and will come latter. At the same day evening when i again contacted them they said they are still checking and there may be some problem of motherboard. Then i contacted to motorola customer care and complaining against misinformation by service centre time by time. Again at evening of 05/08/2017 again i called to service centre then they told me that it can not be repair, i visited agin centre then they told that something track of charging socket was broken and it can not be repairable. According to them it was done by earlier servicing which i had done outside but now there are my quetion...
1. If track was broken then why they can not find out in first instance while they make replacement of charging shocket and delivered as job get it done? It is very possible that it was broken when they are repairing it second time.
2. Why they told me first that there is loosen fitting of charging socket when i visited there second time?
3. They also told me once that there may be problem with mother borad? Why? While track can be easily noticed.
Now my mobile is useless due to negligence and untrained person at there service centre. Who will bear the cost?
Service done with job work srbao[protected] at sai plaza vapi.