Just receiced a 60-day notice of intent to sue . Would appreciate help.

Just receiced a 60-day notice of intent to sue for violation of the safe drinking water and toxic inforcement act of 1986. I am a 3rd party seller of snacks and groceries and I carry a dried fish product which I source from a wholesaler/distributor. The notice names my LLC, the wholesaler and Amazon and claims that the product contains lead. The packaging does not display any hazard warnings, neither does the listing. The products has been sold by numerous amazon 3rd party sellers for years. I send the product to Amazon, who then stores it and ships it to buyers. I have never had a complaint about this product. I do have product liability insurance as Amazon requires it up to $1M. Please advise and thanks in advance.