UBUY Keeps buying from us and returning items, how to stop 3rd party dropshippers?

Ubuy aka Urban Inspirations aka U-Buy, aka, DO3 aka DO6 aka DO9 aka DO etc. is a well known and well despised drop shipper that buys off Amazon US, deliveres packages in NY and WA and then drives accross the border to then ship inside Canada. (They have international locations also where they fly items out of the US. They are Kuwaiti owned and operated.

Anyway, this notorious drop shipper has been buying from us for 8 years and we’ve put up with it. 60% of items are returned to us, 30% are claimed as never received, and only 10% are actually ever kept. They hit us for 8 more seperate items last week. Amazon doesnt care clearly, but what would you do? I’m FBM. Cancel all future items and take the metric hit? In the past we’ve tried canceled a few items but 80% of the time they just reorder in a few days. Every time we ship to them it costs $20 round trip in postage, plus the loss of 20% of our products.

They are well known for doing this, they have changed their name multiple times, Im not sure if its because Amazon closed their accounts way back when, but now they have their names as codes. DO9 or DO2 etc but they have 100’s of complaints from Amazon sellers and buyers in other countries, all their companies and locations have a BBB rating of F, If you look on google maps, their warehouses all have like 20 cameras on the walls, (I guess some sellers show up in person there), They are literally a nightmare to deal with and there is no protection from them.

I cant write them a message or Amazon AI will read it and I’ll get in trouble, I cant cancel the orders or I’ll get a metric hit, I cant report them as that is a waste of time, and Amazon now allows dropshippers more freedoms than in the past, what can I do?