Exactly what philly said. DHL sent me a 300$ bill 2 months after I got the package.
I asked them to provide me with proof that I owe them that (like something I would've signed me that entitles me at paying any fee they give me after I get the package), and they didn't give me any proof. So I haven't paid, but to be honest I live in the fear of some 7' 300lb DHL debt collector coming to my house
So as much as you can... just stay away from them.