new product listing

hi i am new to amazon selling and our product is not available anywhere else we manufacture it ourselves and sell it on our website, i seem to keep running into the same problem when creating new product listing, the asin? we do not have barcodes we have a series of numbers with reference to design/make/model and size so lots of variations? which is why we have a series of relevent numbers and letters is there anything we can do we have watched videos in seller university and chatted twice with amazon and still no further along the line, i even posted to see if their was anyone on social media that had done this before or even sold and no joy(i can see why? ebay was not this bad 25 years ago when listing took hours as apposed to the seconds it takes now to list) feel like amazon are 25 years behind compared to ebay? any help much appreciated and also when listing there should be a button to click for exemption but this is not available when listing?

many thanks paul