SAMSUNG GALAXY A04E DS N/L BLUE phone gets super hot within second day of use

I purchased a SAMSUNG GALAXY A04E DS N/L BLUE online from Makro Montague Gardens after going in there physically and was told that I had the right to return the device within 7 working days if I wasn't happy with it. I purchased it online as I was told that is the only way to purchase through Payflex. I received the phone on Thursday afternoon 5 Dec 2024 and started using it on Friday 6 Dec 2024. The phone started getting very hot (indicating the battery is swelling) by Sunday 8 Dec 2024. I tried calling the customer line and sent an email yesterday with no success and eventually got through this morning, just to be told by a call center agent that I cannot return the phone for a refund or to purchase another brand phone because the phone had already been used! This is against the law. I am within my right to return this device if I am not satisfied. This is DAY 4 of having this horrible phone.