Booked on a flight which I wasn't allowed to take

I recently used Worldwideflights.com to book a return trip from London to Sydney. I specified that I wanted 3 day stopovers in Beijing on the way out, and Shanghai on the return leg, and that the flights would comply with the 72hr visa-free entry requirement, allowing me to spend 3 days at each stopover destination. I was duly booked onto Air China CA0852 departing last Friday, 23rd August, which was scheduled to arrive in Beijing at 0620 the following day, and onwards on CA0175 departing 3 days later, on Tuesday 27th August at 1600. I was assured that these flights were compliant with the requirements for a 72hr visa-free entry into China. However on arrival at Beijing I was told that the onward flight I was booked on was in fact scheduled to stop over in Shanghai for refuelling before flying on to Sydney, and the terms of the 72hr visa free entry specify that you must leave China on a direct flight with no further stops. I therefore was compelled to change onto another flight leaving the previous day, which meant that I only had 2 days in Beijing instead of the 3 I had wanted. Furthermore I had already paid for 3 nights in a hotel there, and was unable to claim a refund for the unused 3rd night's accommodation.
I do feel that this was poor service, the agent should have checked carefully that the onward flight from Beijing was a direct one before booking me onto it.
Very disappointed.