Selling broken stuff and refusing with refund

I bought a microwave and small drone. The microwave is OK, but the drone had a broken camera, the body is scratched all over, full of sand. I couldn't fly it it's old, anyone can see its been used, dented. When I complained and sent them pictures, I was ignored. I requested a RETURN and it was picked up by the courier. The issue now is the refund, they are playing duck and dive, they say they paid on the 23rd of March, today is the 2nd April and I'm still not refunded. I asked for a proof of payment, still dololo