Yep, annoyingly combining postage is still not working.
If you post all the items together, the buyer if they paid for the postage, will receive a postage refund for the 6 unused label, but this will take 30 days.
You also open yourself up to case for item not received as you have proof only, of sending one item.
A bit of a faff, but the best way forward is to cancel the orders, withe the buyer's acceptance so that there's no defect on your account, cancel citing ' Buyer Requests to Cancel, then relist them all together so there's one postage label, one tracking for all the items.
As said, not ideal, and yes we'll agree this should have been solved long ago, as it's affecting all sellers.
One idea, for the time being, some sellers are leaving a message on their listing, for example..... ' If you wish to buy multiple items, please let me know before buying, I will relist them as one listing so only one postage cost is charged, combining postage is not currently possible. '
@sealight_enereb