Horrible experience

I am so disappointed and in disbelief of what happened to me I bought a gas heater at builders in Florida Glen Gordon road on the 10th of June for my mother after 2 weeks she indicated that the heater is faulty and I advised her to give it time to monitor and and if there’s no change I will fetch it and take it back on the 23rd of June I bought another one for my mother in law and when it was delivered my mom asked was was this one sealed with that white seal and hers wasn’t and I said I’m not sure maybe they seal it differently. My mom reached out saying that the heater is faulty and has started building some white residue to show that the gas or flame is not working proper hence it’s creating this. Today I take back the heater I’m assisted by 2 very rude store assistance who told me made me look crazy especially the male one and told me the heater is fine until the slip inside the box which came with the heater proved my assumption correct. The slip is from 2023 Builders sold me a heater which was sent back by someone then they said the employees in receiving might have made that mistake the male said they won’t refund they sending it for repairs. How are you sending it for repairs when you did not sell me a new heater to begin with. So just because it’s an online order it means you can just sell people returned products and get away with it. I left that heater at the store I want my money back. I don’t want it anymore more, I don’t trust the store and it has definitely lost me as a customer.