It's not suddenly. There have always been import charges based on the amount and the item. Were you previous purchases under $20? If so, that would explain why you weren't paying import fees. Additionally, many US sellers are using GSP (global shipping program) which charges the buyer additional fees to cover the cost of the service. These fees are not paid to the seller.
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Non payers should get unpaid item strikes and be added to block bidders lists. Period.