Motorola — Touch not working

Due to touch problem i put my mobile phone (motog2) to service center on 14-8-15 today is 4 october but still my mobile phone is not repaired...they always told the same answer ur mobile part is not available, but will come in 2 days..4 days and still so on...but when i call today they say sir the new part which Motorola send are also defective...so u have to wait upto Monday ...how much i wait now ...this is second time when my touch not working...what i will do if the touch which i received will not work after 1 month when my warrenty period over...secondly, is Motorola the big brand could send the defective piece...? please resolve my problem .