We own our brand but amazon have merged our listings

We own our brand, manufacture and sell the goods on Amazon USA.

Amazon have merged two of our listings. Our best selling ASIN has been moved from its correct product range (a top selling listing), to a different product range, resulting in our sales completely tanking

Amazon states 'Amazon Retail' are the only ones to control the listing, so we are not able to fix it.

We own the brand, and even have the asin in transparency, yet this has still been able to happen. Has anyone experienced this? Or any ideas how we are able to control our own listings?