I've not read through the entire thread but my take on this is if i sell something as working i leave the money in my account until the buyer has received and confirmed they are happy. I always send tracked and usually i pop the buyer a message within a day or two of delivery if they haven't messaged me and just ask if everything has arrived safely and tell them if they have any issues then to let me know. I don't offer a warranty but if something arrived damaged or DOA i would, and have in the past, offered solutions such as replacement, returns, refunds etc. I think with stuff of this age both buyer and seller have to some sort of agreement that you'll ship/receive the item in the advertised condition but beyond that you're on your own. The only time i insist on a buyer having no recourse is if they want uninsured/untracked shipping or declaring lower customs values etc although i tend not to offer shipping abroad that much these days since brexit made it more awkward.