Yeah, looks like it's not limited to eBay though. It's a general trend apparently, to reduce functionality of online tools to the strict minimum and make these tools increasingly inflexible and annoying to use.
The joke's on them
Trying to contact them is a joke, I have to go through "the system", which is the stupid chat bot. Last time when I said "Operator" want to talk to a human it'd give me options on a call back. Now they seem to grey out the input and present me with a multi choice question that goes to one lot to another lot that looked like it was from a flow diagram which had nothing on there with why I wanted to call them.
It started out, on something like this, just so we can transfer you to the right person... etc and pretty much all the irrelevant choices leads to another set of choices and another set and so on, then answers that point me in circles to things already I know then FOB ME OFF from a phone call. I found a URL somewhere
https://community.ebay.co.uk/t5/Buying/how-do-I-contact-ebay-by-phone/td-p/7603285that initiated a callback.
I ordered the UPS yesterday evening which was reduced over £20 and it turned up early today which is unusually quick.
A different one than the picture turned up, it didn't turn on, I expect it to at least turn on so I know it works when I do my testing. Opened the front and I see it had no battery in there contrary to the listing not even the connector.
When I went to either open a case or returns apparently it was too early. So I sent a message to the seller with pictures of what I got, explaining this and said I this is not what I ordered, not as listed or described, I want you to come down here and pick it up. They haven't replied yet.
After getting through to someone at Ebay they looked at listing, the messages and the picture and they opened a case and are going to checkup when the seller replies. If the seller don't cooperate (swap it with one as described in listing or collect for refund) I get refunded and get to keep the item but the option is still there for the seller to pick it up.
I would never buy or trust second hand UPS that don't come with batteries that work out of the box. I'd have to see it work on batteries for a while to assure my confidence that there is nothing wrong with the unit first before I go and buy another battery for longer runtime.