Bought 4 Vietnam Airlines domestic flights on Expedia for £216 each. Was then told by my host in Vietnam that the official cost of a domestic flight was around £50 - £70. The official price quoted by Vietnam Airlines was between £49 and £67. Complained to Expedia. They could not explain why their price was around 5 times the official price. Eventually, they offered to cancel the four flights. They said that I would be charged USD 20 per ticket by way of cancellation fee. In fact, they charged GBP 23 per ticket. They cannot explain why. Their staff have been unable to help. I have found it impossible to get any form of rational explanation from them. I was a regular customer and trusted them to charge fair prices. Clearly, they do not (or they do not any longer).