You may need to get one, since you ostensibly did not comply with the contractual requirement for the delivery of notice of cancellation.
I don't practice in the area of contracts, and I know nothing about VA law. But I think your point is well taken. The purpose of the certified mail and return receipt is to ensure delivery of the notice. The company has acknowledged receipt of the notice. My guess is that should be sufficient, under the contract. They have sufficient notice, in sufficient time, and the contract should not be renewed -- that's my best guess.