It is just like anything else you might buy on line, you need to know your stuff, and when it is a perishible item, it is extra smart to ask around about the seller and/or ask for references.
Personally, I like to see the fish myself before purchasing, and if possible I would like to see the parents of the fish. And although that isn't always practical, I would want to exhaust all those options first. This is where belonging to a club, whether it is local or national you can obtain names of breeders in your area. You can ask other club members if they have purchased fish from this breeder before.
The cichlid network really isn't that large, and usually if someone isn't holding up their end of the deal, it doesn't take long to get around.
I would offer the following tips on shipping fish. Winter time is really not the best time of the year to be shipping fish, and even if you are in a warm state, that doesn't mean that it isn't going through a cold state before it gets to you. December is really one of the worst times of the year, because there is so much freight in the system due to the holidays and it has a greater chance of getting delayed as well as lost! Also, I don't think adult fish ship nearly as well as young juveniles, and 1" fish really ship the best.