Hi Arthur,
Obviously I am biased, but this is exactly the reason we always recommend purchasing real estate with a realtor. They will assist you through the negotiating and closing process to make sure you get the proper documents at the right time.
We don´t have any offices in the Manuel Antonio area, so I can´t give you a specific contact for the Palo Seco area.
We have a good article about the buying process and documents you need here:
Costa Rica Land: the buying processIn your case, you should have gotten a sales contract at the time of the initial deposit. You normally pay at closing, which is when the buyer is signing over the property to you. Hopefully at your own lawyer´s office here in Costa Rica. In that case you are paying because you already technically own the property, it is just a matter of your lawyer completing the formal registration process.
Just as an aside, have you personally inspected the property that you are buying? Also, some there are some shady operators working telemarketing out of Florida selling ¨strange¨property in the Parrita / Palo Seco / Quepos area. They have been known to demand payment up front and sell property as ¨shares¨of a Costa Rican corporation, a format which is misleading.
So I hate to say it, but your wife is right. In the course of my 11 year marriage I have found this to be the case almost 100% of the time