Whoever holds the rights to the book retains those rights. A contract with Pro Audio Voices does not impact the rights. We do not receive any rights by producing the audiobook edition of your book.
No. Contracting with Pro Audio Voices to create an audiobook does not impact the rights held by the book's Copyright Holder. The Client (whoever holds the rights and enters into the contract with PAV) designates who will hold the Production Copyright. Typically, the author retains the audiobook rights, unless they have sold or released them to their publisher.