Hmm maybe it’s specific to Belgium? I remember in Germany you would pick up packages directly from the zollamt (customs office). You would pay any owed tax there, but I don’t remember there being any extra fee.
I know FedEx and UPS offer shipping options that are supposed to pre-pay any owed tax, but I don’t know if they charge a fee to do so and I’ve also had a terrible time getting things through customs using them in other countries.
Was this before the introduction of the IOSS rules? I can't imagine picking something up directly at customs. International shipping volume has increased a lot, customs does not have the capacity to store much.
The new rules have actually made shipping from Aliexpress easier. VAT is displayed and payed to Aliexpress, they handle customs (as long as total order value is less than €150). In practice they consolidate packages from several sellers into one shipment where possible (although of course with a long-tail delay), and fly it to their new distribution center in Luik.
Customs has a small presence, but because VAT is paid they're mostly concerned about other things such as counterfeits.
Last-mile shipping is then done by postal service, without any additional fees.
I know FedEx and UPS offer shipping options that are supposed to pre-pay any owed tax, but I don’t know if they charge a fee to do so and I’ve also had a terrible time getting things through customs using them in other countries.