Abbott — Similac Advance baby formula probable defect or duplicate product

We were using Similac advance since end of May for our 8 months old baby. She used to feed on it without issues. However, we recently ordered 5 packs from Amazon and my baby started refusing the feeds. We fed her 2 packs anyhow but now she is facing acute diarrhoea since 3 days, vomiting, weight loss etc. I am very concerned that something is wrong with the Similac advance pack that I received. I looks similar to my old purchases but the MRP on it is higher.

I need guidance as to where can I get the packs tested if they are original or if something is wrong. Please guide me.