Phone not working

After my Samsung s6 edge plus came back from having the screen replaced it is not working and no one is able to help. From the customer centre on 14th avenue to a technician at clearwater, no one can help and now I sit without a working phone due to their lack of interest and willingness to help. My phone was in working order before it when in to have the screen replaced and now it's not. Pathetic service received all round.