I sell small items (stickers, cards, small drawings etc.) via Etsy marketplace, which I have integrated with the Click&Drop system. Most of these items fit in a small letter.

When I sell to the EU, the IOSS number is automatically applied to these orders, however the IOSS is not supported when sending a small letter. This resulted in customers getting taxed twice (or applied customs charges).

I spoke to Click&Drop helpline and they said this is not supported (and that they're following guidelines), but what I don't understand is why. There's no reason not to have this exempt from the IOSS system, seeing you can easily sell items that just happen to be small enough to fit a normal letter.

It's almost impossible to send such items without incurring extra cost to EU customers, which in turn means loss of business.

I was advised to buy the large letter / small parcel, which supports the IOSS system, but the postage is much more expensive - sometimes several time more expensive than the item I sold. It is just not commercially viable or reasonable.

Surely this is a relatively small adjustment to make, seeing this system is already in place with other categories of letters / parcels?