I need Google indexing issues resolved

I have a print on demand model and because my printers can only do a light background and a dark background for the same designs - I have two separate pages (wht/blk) for the same designed t-shirt. I have used the same page product title in both cases. I also have the same SEO meta descriptions for some pages. This means I have thousands of pages that haven't been indexed. There are quick fixes to some of this but I need some help as there are approx 11,000 not indexed…