Doorbell return

Not sure if im in the right or wrong so wanted to check. I have a few ring cameras and bought an extra one last month. Few days after i got it a sale was on with amazon for 43% off when buying 2. I asked Ring if they would let me pay the difference and send me the 2nd one i could get via the amazon deal. They said no. Buy the discount pair and then send the original back as it was only a few days old. They gave me a UPS to return which i did. Since then i have been unable to get my refund. They dont believe i am who i am. They said they need to verify an email - they tell me they are sending an email which never arrives. Email address is the same in my ring profile (not in spam etc) .... Ask for my phone number - give them this they say again that it isn't my phone number. Its against the same one in my profile and also the same one Ring use to send the pin code when its needed. I also send the UPS tracking which shows it arrived and they signed for it but this still isn't enough to prove who I am and that i returned the goods.Got a text message with an amazon link clicked this and did approve but nothing. After hours trying with them I have finally given in and my last message to them was ' well done you win - just keep my money' they didn't even respond to that!!! I have proof they have the item returned but they wont refund me.... just wondered if maybe i have done something wrong and maybe I was stupid to send one back that was techincally fine even though they said that was ok???