Phone dead not powering

I was working in my office and was receiving many calls on my cellphone so suddently my phone battery was low and then the phone power off because of low battery.. so at that time I also forget my phone charger . So I found one micro USB and also found and 12volt 1amp adapter so I attach the 12volt 1amp adapter through USB cable… after this my phone is not powering on no led nothing display its totally off I go to the market to repair it they are saying that the motherboard has been dead… so I need my contacts and as well as my data… so kindly one please help me out to repair or to recover data from the dead phone.. or is it really dead. I just put the 12volt 1am charger.kindly somebody help.

I also need my phone backup contacts and data.