I too have the same problem, Ebay and their band of so called "Back Office" developers have taken 4 months so far with no update unless I contact them. I cannot add the "specifics" that Ebay are now demanding I add, I cannot update quantities available. In general as my stock on Ebay is depleted I cannot add further stock as I keep getting the error message "Model is not a variation specific" I have been advised to relist the items all 167 currently with some upto 30 variations but if I do that then I loose all the selling history on those listings.
In December I tried to add Parcelforce as one of my couriers, simple I thought. I followed the instructions supplied by PF and went through the process just like I did for DHL, Click and Drop and DPD. When the orders where not being uploaded to the PF portal I contacted Ebay only to be told that the problem was with PF and definitely not with Ebay. After a month of ringing Ebay and PF I was suddenly sent an email by
PF that stated that PF had been in touch with Ebay and Ebay admitted that PF had been blocked from uploading my orders to their portal "due to the fact that PF did not meet Ebay's GDPR criteria.
So I passed the book back to Ebay, despite 4 months plus wait, over 40 telephone calls and two letter of complaint to the Dublin office which were never even acknowledged I am still no further forward.
The whole scenario is absolutely disgraceful and there is no wonder Ebay are loosing sellers and buyers at a massive rate !!