Your "guest" payment was on your credit card?
Unless you wanted to use a PP balance or your bank account, neither of which is as secure as using the card*, the work involved would far outweigh the minor interest cost.
For your second question, many sellers do not post shipping dates quickly. Most sellers do not use "tracking" since all PP requires in a Dispute is Delivery Confirmation. Contact the seller and ask for the shipping date and DC number. Don't expect to get the number, which is irrelevant for you anyway.
*In case of a Dispute, a card gives you a second chance at a refund, through chargeback.