This is why I hate DHL:

Why do they need soooo many different shipping systems, and why do I as the recipient need to care?

I have been in the situation where I was trying to track a package, but because I was in the wrong portal or selected the wrong DHL service, it claimed that it had no idea about the package.

How hard can it be to have one unified tracking number?

Something like:

DHL<SERVICE_CODE><ID>