Multiple SKUs Being Merged

Woke up this morning to various ASINs merged. I don’t know how or why this happened but I have a catalog of 4000+ unique SKUs. About 30 ASINs suddenly have been merged with one or two other SKUs in my catalog. This has caused HUGE problems. Support is not helpful at all. They have asked me the same question five times. I have lost money and time because of this. I don’t know where to begin fixing this problem. These are fast moving SKUs too…