Samsung store Eastgate Mall poor service

This place is pathetic, I sent my phone in for a simple screen replacement, now the motherboard is damaged and my phone failed quality checks, and no one can explain to be how this happened? my phone has been there for a month now and every day they promise that it will be repaired by the end of the week. the staff is poorly educated and very rude. I'm very disappointed on how they treated me as customer.