Cash Crusaders NI CIty

I bought a new Dixon fridge on the 3 August 2022 at N1 City Cash Crusaders. On the 30 August 2022 the fridge stopped working. I called the store on the 2nd September to confirm if I am able to get a refund for the fridge. As the fridge was not fit for purpose, I had less than 30 days and it would not get cold. I noticed there was a yellow substance coming from behind a new Dixon fridge (As confirmed today, this was a Gas issue) . This fridge was not tested in the shop. The store assistance told me they can not give me a refund as they have a 7 day refund period. I have advised her, I only had the fridge for less than 30 days and it was not working this must have been a manufacturing fault with the fridge. She stated they can look into refunding me but the fridge needs to assessed. The fridge was returned to the store on the 4 September 2022 but booked in on the 5 September 2022. Once the fridge was booked in I was advised it can take 7 to 21 days for the fridge to be assessed and they will see if they are able to refund me. I was promised I would get a follow up call. Today as been 23 days after the fridge has been booked in and I had to call the store to follow up as I have heard from them since I booked the fridge in on the 5 September 2022. I was advised today the fridge arrived yesterday and they have fixed the Gas. The gas was the problem, a brand new fridge that I had for less than 30 days ran out of gas! I have expressed to the store agent I am not happy about this out come once again and I would like my money back as this fridge was not fit for purpose, suitable or sustainable. She has advised they are unable to refund me unless the fridge is repaired twice or thrice. I person feel like this is highly unacceptable, as I had the fridge less than 30 days. I would like my money back,please.