Use a laptop / PC with Chrome and you should be able to change the tracking yourself. If not, you will need to contact eBay Customer Services again , they can do this for you, but contact them only very first thing in the morning, at 8 a.m. when the lines first open as there's more chance of Dublin answering.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
@portobelloroadleon