Loads of our products being re-categorised incorrectly

Hi all,
We make and sell mens trouser belts. In the past few weeks we’ve noticed a load of our belts being re-categorised from Fashion/Mens/Accessories/Belts to DIY & Tools/Back Belts (whatever they are).
Subsequently sales have dropped like a stone as they don’t appear when searching in Fashion at all.
I have spoken to Seller Support who looked at it with me and agreed it was wrong then they sent back an automated reply saying that Amazon’s experts believe it is in the correct category already (Back Belts) so will not change it. I have spoken to 3 people at Seller Support who all agree with me and then eventually we get an automated message saying they won’t change it.

Any ideas how I get this solved? Deleting everything and starting again is tempting but fills me with fear.