Samsung Galexy A3 Cell phone

A new cell phone obtained via Vodacom in May 2017. It has given the same problem 5 times - went in for repairs - I think everything that could be replaced was replaced. All data and numbers lost. Screen protector removed (they advised they would have to) but then had to be replaced at my cost. Samsung very good at phoning and apologising, but after the repairs just over a month later the problem started again. Again Samsung apologise. Can no one see this is a dud phone, make a call to whoever and get the phone replaced. My previous Samsung Galexy is still in operation and going into its 4th year with out a problem