Good, I hope it was just the last can. IMO, the Esbilac has more issues than lack of usable calcium. Babies on it are getting serious diarrhea and Failure to Thrive. This is likely the cause of your babies issues right now.
You can use Tums as a calcium source. Don’t buy mint flavored Tums. A change of formula might be enough to stop the diarrhea.
I’m thrilled that he ate the Goat Milk formula. Sometimes they reject a new taste.