why is it I can no longer chat to a 'real' agent?
eBay has removed many direct links to live agent chat requests, which would seem to indicate it was an intentional choice to remove that option.
And why is it call back times are now in excess of 20 minutes?
Typically that indicates that there is an ongoing problem and that call volumes are higher than normal. Check the community boards to see what is going on and whether it is related to your issue, see if there are any workarounds or fixes, and avoid calling unless your matter is pressing and cannot be addressed using other channels. Or wait a bit and try again when call volumes have subsided.
Try contacting eBay via social media:
https://x.com/askebay
https://www.facebook.com/ebay
https://www.instagram.com/ebayforsellers/