Since April, Ebay have been rolling out Simple Delivery which is now mandatory for private sellers for most categories.
You won't get the postage back because the buyer pays Ebay directly for the postage. If you don't use the label, the buyer gets a refund, not you. You should be able to change the tracking from the dropdown menu.
You can opt to use Royal Mail only (DHL for large items) and arrange collection for your parcels.
if you plan to continue selling, do read about how Simple Delivery works. Follow the links and read all the FAQs to see if/how you can adapt Simple Delivery to your sales and circumstances.
https://www.ebay.co.uk/help/selling/posting-items/setting-postage-options/simple-delivery?id=5575&st...
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)