Terrible, terrible service. Never use Opodo! I booked flights with them to the USA. I requested flights to RDU. They said there were none (there are), so I booked to CLT instead - a 2 hour drive away. When I discovered there were flights to RDU, and asked to change my flights the same day I booked the original flights, they said I would lose all my money. I asked for a phone number or email address to submit a complaint and they gave me some no-reply type email address that generated an auto reply, and no response to my complaints.
I paid an extra £400 for a flexible return date. When I tried to change my return, they said there were literally NO FLIGHTS. There were, of course, but I had to book directly through United, and paid an extra £600 as United had no record of the flexible fare.
Two days ago I got an email from Opodo saying that my return flights have been cancelled. I am currently on hold trying to figure out what this means. I have twice been cut off by the call centre in India, having waited for 40 minutes. The online chat facility on their website requires you to have a Facebook account, which I don't have. I have wasted an enormous amount of time and money and never experienced such terrible customer service in my entire life. AVOID!