$100 charge difference for Fedex shipping label

[savvyfalcon]

On April 27, I generated a Fedex shipping label trough eBay for an international order. The label cost at the time of generation was around $50. Fast forward to today, I see a charge of $141 from Fedex with no mention of wrong measurements or any explanation. I usually overstate the packages measurement and weight to avoid errors. I called eBay customer service and the agent had no explanation to provide other than that the amount I saw during issuance of the label was just an estimate. Is it normal and fair that the actual charge be almost $90 different from the estimate? The agent wasn't convinced that I will even win the dispute and saw that as normal. 

Note: this is the 2nd time this happens with me. In the first time, eBay customer service was more helpful and understanding. I ended up winning the dispute.

[brettjet38]

UPS / FedEx, you use at your own risk; they are notorious for "unexpected" charges, as already stated.