I ordered something from a Chinese company and they quoted me 5USD per unit and 35USD shipping. I accepted and the units were shipped and delivered and of excellent quality.

Sometime later FedEx sends me a weird bill for some random seeming amount of money I owed. They had a link or email or something to basically refuse to pay. I did refuse to pay. The shipper ended up communicating with me to determine I was going to refuse to pay and I found where Fedex had on the website that indicated the shipper was responsible for all fees. I assume the randomness of it was related to tariffs but I wasn't going to pay anything like what they sent me.

I do hope that some repercussions come of these terrible economic policies and the shipper gets their money back from Fedex, but as a company or as an individual I don't think a company's policy to send random bills after delivery is valid either.

I've had this before, a few years ago, and a quick google at the time seemed to show that a fair few other people have. I'm in the UK, and about 6 months after buying something small from China (iirc), we got an £10 invoice for a "disbursement fee" from Fedex. It was very vague as to what the fee was actually for. I assume it was just a "scam" by Fedex to get more money.

This sounds familiar. Months after not receiving an order, UPS sent a letter from a pseudo(?) collection agency for a charge added to the order. But there was no way to pay for it - as there was a statement that only the shipper could pay, but still, the order didn't arrive - it was very confusing, the shipment disappeared in paperwork - and no one could figure it out. Customer was out the original purchase fee, producer never could reviver shipment. Complete mess.