I've had DHL collect sales tax after Ebay has collected sales tax, and weird tariff fees too. Usually it's not enough to get me to challenge the charge. Iowa sales tax is 6%, it was 2% when I was a kid. No VAT, of course the US is not a stellar example of fiscal discipline
I hate dealing with DHL - they tried to collect a tariff off me when I sent Sover Wong an F2 for service! They wanted to charge a 'tax' as if I was buying the camera from him even though:
1/ there is no tax on camera purchases
2/ there was no purchase, it was an item sent for service.
Luckily before all this, I had made sure to fill out all the pro-forma paperwork explaining what was going on. Initially they tried to claim that it was too bad, just because they had missed looking at my paperwork, I would have to pay. I got into it with them, saying I was not going to pay for their admitted errors, and that was when they backed down.
It seems that the way DHL works is to try to add as many 'fees' on top of the already paid for shipping after the fact, and see what they can get away with.
I let Sover know, and he said he wouldn't use DHL any more. Not sure if that is the case or not.