Item and contract for sale executed at the personal residence, then invoiced through a, business, now the business is bankrupt ,is the personal sale negated
The answer depends on facts that are not provided.
It really does not matter where a sale occurs. A purchase of a book from Amazon.com is completed at your residence, but it is still a transaction with the business. Location is not determinative.
What would be determinative is the language of the contract of sale that you refer to. If the contract of sale identifies the "seller" as the business, then it would be difficult to now argue that you were buying from an individual and not a business. If, however, the contract of sale identifies the seller as an individual, then you may have an argument.