NOKIA N6 - Cell phone destroyed by service centre

I had got a problem with my cell Phone Nokia N-* at *:** am morning on **.**.****. I had called at Nokia karnal Service Centre located at SCO ***, First Floor, Mughal Canal, Karnal-******. They said within *-* days our phone will be repaired. We called them on **.**.**** but they told that it will take at least more one week. On **.**.**** and **.**.**** we visited the service centre again and found that they had prepared the job worksheet on **.**.****. Really shocking that they had prepared the job worksheet after * days. They replied that we prepare two job worksheet one manually which is already prepared on **.**.**** and further said one part sub-board is damaged and at least one week will be taken for phone repair. On **.**.**** they said we have availability at our Panipat branch office. They told that we will return the same on or before *:** pm after repair it. But today they are saying the motherboard is also damaged. Nothing about motherboard is mentioned on job sheet no. *********/******/***.
As per my knowledge, I am sure the staff of the service centre has damaged the cell phone.