I've been selling on eBay for almost a year now, and it's unbelievable how many stupid problems they have that they can't seem to fix.
I have also had the problem where the auto-login doesn't work. I use KeyPass and KeyFox plugin in Firefox, but there is something about the eBay login page that prevents KeyFox from entering the login info. A small issue, but it gets annoying when you have to log in so often.
Another problem is that every once in a while it just forgets the second line of my return address on the packages I ship. This line has my apartment number. It just disappears. I go to my "ship from" address in my account setup and find there are like 100 duplicate addresses in there all without the second line and one with it. I spend ages deleting each one and waiting for the page to refresh between each time I click a "delete this address" link, and finally get it back down to the one correct address. It will be fine for a few days to a month or so, then it happens again.
Sending messages to eBay support is equivalent to sending to /dev/null. I've never EVER received a response from their customer service.
I do get a response if I tweet to @AskEbay. They respond quite quickly but often seem to be unable to address the issues, like the address issue. When I complain on twitter to @AskEbay about customer service not responding to messages they tell me to call the customer support phone number. Really? I don't want to talk to a person, I just want to send a message, where I can write what I need to say without some phone person insisting on following some script that doesn't pertain to why I'm calling.
Then there are all their new policies to make things difficult for the seller. I had one buyer who wanted to return an item. From his message it was clear he had no idea what he bought or how to use it. I had the listing set as "No Returns." That doesn't matter to eBay. If the buyer says the item was defective or not as advertised they will let the buyer return it anyway and charge the seller for shipping, which is what the buyer did. I ranted to eBay about that and they said they are trying to create the best experience for buyers. I complained that I shouldn't have to pay return shipping since the item worked fine, and now I have an open item returned that I can't sell as new. They refunded the return shipping cost.
So then I started listing my stuff with 14 day returns. At least that way I can specify that the buyer pays return shipping. After nearly a year and 170 packages shipped with only one return and one late shipping (post office's fault) they "awarded" me "Top Rated Seller" status. Except that the top rated seller logo won't appear on any of my listings unless I offer 30 day returns. Guess that doesn't matter since I've never had a buyer return an item except for that one guy who didn't know what he bought. So I changed all my stuff to 30 day returns.
Oh, I offer all my stuff with free shipping. Nobody seems to want to buy cell phone batteries and commodity stuff like that if you don't. But I noticed on lots of my listings the "Free Shipping" logo was not appearing. It turns out that if I just click the "offer free shipping" check box, most of the time that orange "free shipping" symbol they overlay on the corner of the pictures doesn't show. But I found if I checked that I wanted to specify my own shipping and enter the size and weight of the package, wait for it to tell me an estimated cost, then check the box that lets me specify a cost, enter zero, then click back to the first tab and check the box that says "free shipping" then the logo will show on the images.
And don't even get me started on their eBay VeRO program crap where anyone who lays claim to a trademark can kill any listing on eBay they don't like with no recourse for the seller. If I rant about that it will be another 4 paragraphs to tell that story.