Bought iPhone 7 on eBay. Had a 10 day cooling period to send back. Contacted them in time but no reply. What to do next?

So 2 months ago I bought an iPhone 7 on eBay for When I received the phone I realised that it wasn't what I wanted and the description on the phone told me I had 10 days cooling down period which means I could send it back within 10 days of receiving it without any reason. I emilaid them within 6 days of receiving it and they did not contact me back. I went and contacted PayPal, my credit card holder etc and nobody did anything. Just wondering what should I do now as I do want to get my money back as the phone is not what I wanted.

You log into ebay and inititate a return for the item.

Trouble being that you needed to to do that about 6 weeks ago.
All you can do now is sell the handset onward.
Preferably face to face and paid in cash

This won't help you, but this situation is why I hesitate buying larger priced items online. I prefer to deal locally in the event of a return.