Two eans on one asin, support can't do anything about it

Hi! Please can anyone help with their advice or maybe a senior support manager will take notice?

We ran into a problem: suddenly one asin consisted of two eans. Because of this, we have problems with revenue, we can't advertise, we can't make a variation with this asin. What to do? We created a lot of cases, provided statements confirming that we are the manufacturer and we are the brand holder, provided an extract from the registry that this ean really belongs to the product. And it's all to no avail, for a month now the support has done absolutely nothing.

What do we need is to create only one correlation: one ean and one asin. We're getting discouraged by the unwillingness to help us.