American Swiss review: Returns policy

Hello, I bought a ring and earrings earlier in the year. I went back to complain about the ring. even the sales clerk said it was badly made. They allowed me to exchange it for a different ring which i had to pay an additional amount for. This was on 8 nov 2019. I then went this morning to the store to return the ring as i find the diamonds are extremely yellow in the day light. They will not credit me for the ring as apparently "its used goods" now...they are scratches on it. There are most definitely no scratches on the ring! I have the box, the receipt and the ring in good condition and all within the 30 days. To top it all off the store manager had to call the area manager and the area manager wanted to talk to me on the telephone. She ended up yelling at me down the phone for no reason whatsoever. I am made to feel like the guilty party when i have done nothing other then want to return a purchase. I was asked why am i returning the ring now? Why not its within the 30 day period as stipulated!