Trying to unmerge/split ASINs

For the past three weeks, after over twenty phone calls and opening numerous cases trying to split ASINs have so far drawn a complete blank.

I sell reading glasses with frame colour and lens strength variations, each variation has its own SKU, EAN and differing quantities, yet somehow over the past few months my variations have been covered with the same ASIN, therefore I have two, three, four even five products that now look the same.

Amazon have asked me to supply the original ASIN which I don’t have until the ASINs have been split/unmerged, occasionally I reach someone in the catalogue team who understands the issue, I supply a list of ASINs, they don’t reply, you then have to start all over again.

I’m just going round in circles with only Amazon able to split/unmerge ASINs, can anybody assist?