never lay-bye a phone here

i lay-byed a samsung galaxy j1 phone when i went to take it out i asked if i can exchange it before i take it out as i heard that the phone has network problems the lady said no even though she was struggling to catch network until we put our own sim it worked for a bit but when we got home it never worked so we tried returning it as per 7days return policy but the rude ladies at till said the is no exchanged for laybye so i paid for nothing as i will never use this useless phone in my area