Hey aardvark sandwich. I'm sorry to hear about your situation . I believe you have honestly done everything you could on your end to remedy the situation. Personally if I found a can I didn't like, I would just resell them on my own. I just brought 3 cans recently (last couple months) that didn't work out for me and I've sold all two of them and going to sell the third. You done your fair share on the deal and then some by responding quickly to ship out the adapter and accommodate the buyer.
X2. I wouldn't want to deal with him either.