eBay have Fastway as one of the tracking options in 'Carrier', so if you sent it with Fastway then try uploading the tracking number that works with their website. Whichever works with their website should be the number to upload to eBay tracking.

I checked for Couriers Please and couldn't find it listed in eBay's service but just check for whichever company you're sending the parcel with. eBay has quite a few there.