Sorry. I was sure that the couriers own tracking number was obscurely recorded in Sendles tracking page but on checking i can see it does not. ( the email that receivers get may have different info) The sender could tell you the courier and the actual tracking as its printed on the label. If its Metro to Metro would be Couriers please, otherwise Aramex, i am fairly sure Sendle doesnt use anyone else, all other couriers are more expensive than those two.
I ship up to 50 cartons a week by road or air using Couriers Please, Aramex(FedEX), Toll or MNX. IMO the majority of problems with couriers rest with senders, but what would I know