OP - please advise where you are originating from. I have a feeling that you are not starting from the US. Oneway in C and oneway in Y is NOT going to what you'd want to be paying if you're originating from the USA.

Besides - you can't check with VN themselves -as the booking was made with your agent - which means it will be on a system that they are using. Also it is not something they ' are coming up with themselves' - it sounds more like what you don't know what to ask for and the local agencies are taking you for a ride.

Please advise us where you are starting your trip from.. ..hold on.. I think I know after re-reading your post.

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Correct me if I am wrong....

You are now in Vietnam. And you have contacted a local tour company to go from Vietnam to Siem Rep. And the dates that you want to go are full on VN.

Well, there are other airlines that fly the route other than VN. There's Bangkok Airways (PG), and their fares are much cheaper than Vietnam Airlines. For tours, you really do NOT need to go through a tour agency from Vietnam unless you want a Vietnamese guide. You may do it as a free and easy package. ie book your flights and hotels. And when you are in Siem Rep, your hotel will refer you to a local guide who will be more than happy to take you around and in the language of your choice! Much cheaper too.

And more freedom without being shuffled around like herds of sheep! You get to see what the tour package shows you - and you will always be in a crowded situation. I went on my own (with a friend), and we went with a local guide.. and we went against the local tour groups so that there was a time when we were literally the only people at Angkor Wat! You really can't beat that !