OnedayOnly Too good to be true

I purchased two iphones on OnedayOnly which were faulty from the start. The batteries were swollen and the phones got so hot, it could have exploded anytime. I send it back with even the original packaging after spending R700 per phone on the day we received it for screens and covers. According to OnedayOnly, the phones were tested and safe to use. They will not refund me for the R1 400 spend on the phones but promised me a full refund of almost R6 000 that I paid for the phones. I have been waiting since the 21st of October 2024. The person who initially helped me through the process, has since disappeared and now they are sending me automated messages which makes no sense. The refund was apparently processed in December last year, but still nothing.